A collection of algorithm and data structure implementations in Java, along with code generation helpers for web frameworks. All algorithm methods are annotated with time and space complexity via @InterestingAlgorithm.
| Category | Package | Highlights |
|---|---|---|
| Linked Lists | linkedlist | Doubly linked list, LRU cache (HashMap + linked list), singly linked list operations (reverse, cycle detection, intersection detection, merge sorted lists) |
| Trees | trees | BST operations, tree traversals (pre/in/post-order, level-order, iterative + recursive), sorted array/list to BST, trie with prefix search, height/balance checks |
| Heaps | heap | Max heap (tree-based), min heap (array-based) |
| Queues | queues | Min priority queue (binary heap-backed), circular buffer |
| Sets | sets | Disjoint set / union-find with path compression and union by rank |
| Graphs | graph | Graph, vertex, edge representations |
| Category | Package | Highlights |
|---|---|---|
| Graph Algorithms | graph | BFS, DFS, Dijkstra's shortest path, Bellman-Ford, topological sort, cycle detection, Kruskal's MST, Prim's MST, strongly connected components (Kosaraju's) |
| Dynamic Programming | dp | 0/1 knapsack, unbounded knapsack, coin change (min coins + ways), longest increasing subsequence, edit distance, matrix chain multiplication, rod cutting, longest palindromic substring, Kadane's max subarray, unique paths, min path sum |
| Backtracking | backtracking | N-queens, generate parentheses, subsets (power set), permutations, combination sum, word search, sudoku solver |
| Sliding Window | slidingwindow | Max sum subarray of size K, longest substring without repeating chars, minimum window substring, longest substring with K distinct chars, sliding window maximum |
| Two Pointers | twopointers | Two sum, three sum, container with most water, trapping rain water, remove duplicates in sorted array |
| Stack Problems | stackproblems | Valid parentheses, evaluate reverse Polish notation, daily temperatures, largest rectangle in histogram, min stack (O(1) getMin) |
| Binary Search | binarysearch | Search rotated array, find first/last position, search 2D matrix, find peak element, integer sqrt, find min in rotated sorted array |
| Sorting | sort | Quicksort, mergesort, introsort, heapsort, bubblesort, selection sort, radix sort |
| Arrays | arrays | Spiral matrix, merge sorted arrays, interval merging, equilibrium indices, permutations, combinations, binary search, two-number sum |
| Strings | strings | Palindrome detection, longest common substring/subsequence, anagram detection, string reversal, diff |
| Words | words | Soundex, rhyming detection, syllable splitting, text justification, Roman numeral conversion, N-grams, word frequency |
| Math | math | Arithmetic expression evaluation, sieve of Eratosthenes, prime factorization, combinatorics (nCk, Catalan, Pascal's triangle), quadratic solver, GCD/LCM, atoi/itoa |
| Finance | math/finance | Stock profit (single/multiple transactions), peak/valley detection, volatility |
| Sequences | sequence | Hamming distance, Levenshtein distance, Needleman-Wunsch scoring, Hirschberg alignment |
| Bit Manipulation | bits | Bitwise operations, bitmap, bitset |
| Misc | misc | Fibonacci, Excel column conversions, FizzBuzz, climb stairs (DP), Unix path simplification, version comparison, peak element |
| Graphics | graphics | Image erosion/dilation, Manhattan distance, color averaging, paint fill, convex hull |
| Games | games | Sudoku generator, Game of Life, Reversi, word square, crossword, Rubik's cube |
Scaffolding helpers for web frameworks, generating CRUD application boilerplate:
- Rails (
gen/rails) - Implemented - Spring MVC (
gen/springmvc) - Partial - MEAN (
gen/mean) - Partial
Java (no build system — compile with javac)
# Compile (excluding alg/io which requires Apache Commons IO)
javac -d build $(find alg test -name "*.java"! -path "*/io/*"! -name "WebTest.java"! -name "WordTest.java")# Run tests
java -cp build test.alg.misc.MiscUtilsTest
java -cp build test.alg.tree.TreeTest
java -cp build test.alg.sort.SortTest
java -cp build test.alg.math.MathTest
java -cp build test.alg.arrays.ArraysTest