serialize deserialize binary tree

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()

data_structures/binary_tree/serialize_deserialize_binary_tree.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from dataclasses import dataclass
+
+
+@dataclass
+class TreeNode:
+ """
+ A binary tree node has a value, left child, and right child.
+
+ Props:
+ value: The value of the node.
+ left: The left child of the node.
+ right: The right child of the node.
+ """
+
+ value: int = 0
+ left: TreeNode | None = None
+ right: TreeNode | None = None
+
+ def __post_init__(self):
+ if not isinstance(self.value, int):
+ raise TypeError("Value must be an integer.")
+
+ def __iter__(self) -> Iterator[TreeNode]:
+ """
+ Iterate through the tree in preorder.
+
+ Returns:
+ An iterator of the tree nodes.
+
+ >>> list(TreeNode(1))
+ [1,null,null]
+ >>> tuple(TreeNode(1, TreeNode(2), TreeNode(3)))
+ (1,2,null,null,3,null,null, 2,null,null, 3,null,null)
+ """
+ yield self
+ yield from self.left or ()
+ yield from self.right or ()
+
+ def __len__(self) -> int:
+ """
+ Count the number of nodes in the tree.
+
+ Returns:
+ The number of nodes in the tree.
+
+ >>> len(TreeNode(1))
+ 1
+ >>> len(TreeNode(1, TreeNode(2), TreeNode(3)))
+ 3
+ """
+ return sum(1 for _ in self)
+
+ def __repr__(self) -> str:
+ """
+ Represent the tree as a string.
+
+ Returns:
+ A string representation of the tree.
+
+ >>> repr(TreeNode(1))
+ '1,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3)))
+ '1,2,null,null,3,null,null'
+ >>> repr(TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5))))
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ return f"{self.value},{self.left!r},{self.right!r}".replace("None", "null")
+
+ @classmethod
+ def five_tree(cls) -> TreeNode:
+ """
+ >>> repr(TreeNode.five_tree())
+ '1,2,null,null,3,4,null,null,5,null,null'
+ """
+ root = TreeNode(1)
+ root.left = TreeNode(2)
+ root.right = TreeNode(3)
+ root.right.left = TreeNode(4)
+ root.right.right = TreeNode(5)
+ return root
+
+
+def deserialize(data: str) -> TreeNode | None:
+ """
+ Deserialize a string to a binary tree.
+
+ Args:
+ data(str): The serialized string.
+
+ Returns:
+ The root of the binary tree.
+
+ >>> root = TreeNode.five_tree()
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> root is deserialized # two separate trees
+ False
+ >>> root.right.right.value = 6
+ >>> root == deserialized
+ False
+ >>> serialzed_data = repr(root)
+ >>> deserialized = deserialize(serialzed_data)
+ >>> root == deserialized
+ True
+ >>> deserialize("")
+ Traceback (most recent call last):
+ ...
+ ValueError: Data cannot be empty.
+ """
+
+ if not data:
+ raise ValueError("Data cannot be empty.")
+
+ # Split the serialized string by a comma to get node values
+ nodes = data.split(",")
+
+ def build_tree() -> TreeNode | None:
+ # Get the next value from the list
+ value = nodes.pop(0)
+
+ if value == "null":
+ return None
+
+ node = TreeNode(int(value))
+ node.left = build_tree() # Recursively build left subtree
+ node.right = build_tree() # Recursively build right subtree
+ return node
+
+ return build_tree()
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()