print reverse: A LinkedList with a tail pointer

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")

DIRECTORY.md

@@ -50,6 +50,7 @@
  * [Index Of Rightmost Set Bit](bit_manipulation/index_of_rightmost_set_bit.py)
  * [Is Even](bit_manipulation/is_even.py)
  * [Is Power Of Two](bit_manipulation/is_power_of_two.py)
+ * [Largest Pow Of Two Le Num](bit_manipulation/largest_pow_of_two_le_num.py)
  * [Missing Number](bit_manipulation/missing_number.py)
  * [Numbers Different Signs](bit_manipulation/numbers_different_signs.py)
  * [Reverse Bits](bit_manipulation/reverse_bits.py)
@@ -322,6 +323,7 @@
  * [Integer Partition](dynamic_programming/integer_partition.py)
  * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
  * [Knapsack](dynamic_programming/knapsack.py)
+ * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
  * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
  * [Longest Common Substring](dynamic_programming/longest_common_substring.py)
  * [Longest Increasing Subsequence](dynamic_programming/longest_increasing_subsequence.py)
@@ -460,6 +462,7 @@
 ## Greedy Methods
  * [Fractional Knapsack](greedy_methods/fractional_knapsack.py)
  * [Fractional Knapsack 2](greedy_methods/fractional_knapsack_2.py)
+ * [Gas Station](greedy_methods/gas_station.py)
  * [Minimum Waiting Time](greedy_methods/minimum_waiting_time.py)
  * [Optimal Merge Pattern](greedy_methods/optimal_merge_pattern.py)
 
@@ -542,6 +545,7 @@
  * [Average Median](maths/average_median.py)
  * [Average Mode](maths/average_mode.py)
  * [Bailey Borwein Plouffe](maths/bailey_borwein_plouffe.py)
+ * [Base Neg2 Conversion](maths/base_neg2_conversion.py)
  * [Basic Maths](maths/basic_maths.py)
  * [Bell Numbers](maths/bell_numbers.py)
  * [Binary Exp Mod](maths/binary_exp_mod.py)
@@ -657,7 +661,6 @@
  * [P Series](maths/series/p_series.py)
  * [Sieve Of Eratosthenes](maths/sieve_of_eratosthenes.py)
  * [Sigmoid](maths/sigmoid.py)
- * [Sigmoid Linear Unit](maths/sigmoid_linear_unit.py)
  * [Signum](maths/signum.py)
  * [Simpson Rule](maths/simpson_rule.py)
  * [Simultaneous Linear Equation Solver](maths/simultaneous_linear_equation_solver.py)
@@ -716,6 +719,7 @@
  * [Leaky Rectified Linear Unit](neural_network/activation_functions/leaky_rectified_linear_unit.py)
  * [Rectified Linear Unit](neural_network/activation_functions/rectified_linear_unit.py)
  * [Scaled Exponential Linear Unit](neural_network/activation_functions/scaled_exponential_linear_unit.py)
+ * [Sigmoid Linear Unit](neural_network/activation_functions/sigmoid_linear_unit.py)
  * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
  * [Convolution Neural Network](neural_network/convolution_neural_network.py)
  * [Perceptron](neural_network/perceptron.py)
@@ -1180,6 +1184,7 @@
  * [Naive String Search](strings/naive_string_search.py)
  * [Ngram](strings/ngram.py)
  * [Palindrome](strings/palindrome.py)
+ * [Pig Latin](strings/pig_latin.py)
  * [Prefix Function](strings/prefix_function.py)
  * [Rabin Karp](strings/rabin_karp.py)
  * [Remove Duplicate](strings/remove_duplicate.py)

data_structures/linked_list/print_reverse.py

@@ -1,22 +1,91 @@
 from __future__ import annotations
 
+from collections.abc import Iterable, Iterator
+from dataclasses import dataclass
 
+
+@dataclass
 class Node:
- def __init__(self, data=None):
- self.data = data
- self.next = None
+ data: int
+ next_node: Node | None = None
+
+
+class LinkedList:
+ """A class to represent a Linked List.
+ Use a tail pointer to speed up the append() operation.
+ """
+
+ def __init__(self) -> None:
+ """Initialize a LinkedList with the head node set to None.
+ >>> linked_list = LinkedList()
+ >>> (linked_list.head, linked_list.tail)
+ (None, None)
+ """
+ self.head: Node | None = None
+ self.tail: Node | None = None # Speeds up the append() operation
+
+ def __iter__(self) -> Iterator[int]:
+ """Iterate the LinkedList yielding each Node's data.
+ >>> linked_list = LinkedList()
+ >>> items = (1, 2, 3, 4, 5)
+ >>> linked_list.extend(items)
+ >>> tuple(linked_list) == items
+ True
+ """
+ node = self.head
+ while node:
+ yield node.data
+ node = node.next_node
+
+ def __repr__(self) -> str:
+ """Returns a string representation of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.extend([2, 3, 4, 5])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4 -> 5'
+ """
+ return " -> ".join([str(data) for data in self])
 
- def __repr__(self):
- """Returns a visual representation of the node and all its following nodes."""
- string_rep = []
- temp = self
- while temp:
- string_rep.append(f"{temp.data}")
- temp = temp.next
- return "->".join(string_rep)
+ def append(self, data: int) -> None:
+ """Appends a new node with the given data to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> str(linked_list)
+ ''
+ >>> linked_list.append(1)
+ >>> str(linked_list)
+ '1'
+ >>> linked_list.append(2)
+ >>> str(linked_list)
+ '1 -> 2'
+ """
+ if self.tail:
+ self.tail.next_node = self.tail = Node(data)
+ else:
+ self.head = self.tail = Node(data)
 
+ def extend(self, items: Iterable[int]) -> None:
+ """Appends each item to the end of the LinkedList.
+ >>> linked_list = LinkedList()
+ >>> linked_list.extend([])
+ >>> str(linked_list)
+ ''
+ >>> linked_list.extend([1, 2])
+ >>> str(linked_list)
+ '1 -> 2'
+ >>> linked_list.extend([3,4])
+ >>> str(linked_list)
+ '1 -> 2 -> 3 -> 4'
+ """
+ for item in items:
+ self.append(item)
 
-def make_linked_list(elements_list: list):
+
+def make_linked_list(elements_list: Iterable[int]) -> LinkedList:
  """Creates a Linked List from the elements of the given sequence
  (list/tuple) and returns the head of the Linked List.
  >>> make_linked_list([])
@@ -28,43 +97,30 @@ def make_linked_list(elements_list: list):
  >>> make_linked_list(['abc'])
  abc
  >>> make_linked_list([7, 25])
- 7->25
+ 7 -> 25
  """
  if not elements_list:
  raise Exception("The Elements List is empty")
 
- current = head = Node(elements_list[0])
- for i in range(1, len(elements_list)):
- current.next = Node(elements_list[i])
- current = current.next
- return head
+ linked_list = LinkedList()
+ linked_list.extend(elements_list)
+ return linked_list
 
 
-def print_reverse(head_node: Node) -> None:
+def in_reverse(linked_list: LinkedList) -> str:
  """Prints the elements of the given Linked List in reverse order
- >>> print_reverse([])
- >>> linked_list = make_linked_list([69, 88, 73])
- >>> print_reverse(linked_list)
- 73
- 88
- 69
+ >>> in_reverse(LinkedList())
+ ''
+ >>> in_reverse(make_linked_list([69, 88, 73]))
+ '73 <- 88 <- 69'
  """
- if head_node is not None and isinstance(head_node, Node):
- print_reverse(head_node.next)
- print(head_node.data)
+ return " <- ".join(str(line) for line in reversed(tuple(linked_list)))
 
 
-def main():
+if __name__ == "__main__":
  from doctest import testmod
 
  testmod()
-
- linked_list = make_linked_list([14, 52, 14, 12, 43])
- print("Linked List:")
- print(linked_list)
- print("Elements in Reverse:")
- print_reverse(linked_list)
-
-
-if __name__ == "__main__":
- main()
+ linked_list = make_linked_list((14, 52, 14, 12, 43))
+ print(f"Linked List: {linked_list}")
+ print(f"Reverse List: {in_reverse(linked_list)}")