# JavaScript Algorithms and Data Structures [![Build Status](https://travis-ci.org/trekhleb/javascript-algorithms.svg?branch=master)](https://travis-ci.org/trekhleb/javascript-algorithms) [![codecov](https://codecov.io/gh/trekhleb/javascript-algorithms/branch/master/graph/badge.svg)](https://codecov.io/gh/trekhleb/javascript-algorithms) ## Code Examples ### Data Structures 1. [Linked List](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/linked-list) 2. [Queue](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/queue) 3. [Stack](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/stack) 4. [Hash Table](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/hash-table) 5. [Heap](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/heap) 6. [Priority Queue](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/priority-queue) 7. [Trie](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/trie) 8. [Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree) * [Binary Search Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree/binary-search-tree) * [AVL Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree/avl-tree) * B-Tree * 2-3 Tree * Red-Black Tree * Suffix Tree * Segment Tree or Interval Tree * Binary Indexed Tree or Fenwick Tree 9. [Graph](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/graph) ### Algorithms * **Math** * [Fibonacci Number](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/fibonacci) * [Cartesian Product](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/cartesian-product) * [Power Set](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/power-set) * [Primality Test](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/primality-test) - trial division * [Euclidean Algorithm](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/euclidean-algorithm) - calculate the greatest common divisor (GCD) * Collatz Conjecture algorithm * Extended Euclidean algorithm * Find Divisors * Fisher-Yates * Greatest Difference * Least Common Multiple * Newton's square * Shannon Entropy * **String** * [String Permutations](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/string/permutations) * Combination * Minimum Edit distance (Levenshtein Distance) * Hamming * Huffman * Knuth Morris Pratt * Longest common subsequence * longest common substring * Rabin Karp * **Search** * [Binary Search](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/search/binary-search) * **Sorting** * [Bubble Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/bubble-sort) * [Selection Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/selection-sort) * [Insertion Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/insertion-sort) * [Heap Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/heap-sort) * [Merge Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/merge-sort) * [Quicksort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/quick-sort) * [Shellsort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/shell-sort) * **Graph** * [Depth-First Search (DFS)](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/graph/depth-first-search) * [Breadth-First Search (BFS)](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/graph/breadth-first-search) * Detect Cycle * Topological Sorting * Dijkstra Algorithm to Find Shortest Path * Eulerian path, Eulerian circuit * Bellman Ford * Strongly Connected Component algorithm * Shortest Path Faster Algorithm (SPFA) * **Tree** * Depth-First Search (DFS) * Breadth-First Search (BFS) * **Minimum Spanning Tree** * Prim’s algorithm * Kruskal’s algorithm * **Dynamic Programming** * Increasing subsequence * Knapsack problem * Maximum subarray * Maximum sum path * Integer Partition * Longest common Subsequence * Longest Increasing subsequence * Shortest common supersequence * **Uncategorized** * Union-Find * Maze ## Running Tests **Run all tests** ``` npm test ``` **Run tests by name** ``` npm test -- -t 'LinkedList' ``` ## Playground You may play with data-structures and algorithms in `./src/playground/playground.js` file and write tests for it in `./src/playground/__test__/playground.test.js`. Then just simply run the following command to test if your playground code works as expected: ``` npm test -- -t 'playground' ``` ## Useful links * [Data Structures and Algorithms on YouTube](https://www.youtube.com/playlist?list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8) * Algorithms * Dynamic Programming * [Introduction to Dynamic Programming 1](https://www.hackerearth.com/practice/algorithms/dynamic-programming/introduction-to-dynamic-programming-1/tutorial/) ## Useful Information ### Big O Notation Order of growth of algorithms specified in Big O notation. ![Big O graphs](https://github.com/trekhleb/javascript-algorithms/blob/master/assets/big-o-graph.png) Source: [Big O Cheat Sheet](http://bigocheatsheet.com/). Below is the list of some of the most used Big O notations and their performance comparisons against different sizes of the input data. | Big O Notation | Computations for 10 elements | Computations for 100 elements | Computations for 1000 elements | | -------------- | ---------------------------- | ----------------------------- | ------------------------------- | | **O(1)** | 1 | 1 | 1 | | **O(log N)** | 3 | 6 | 9 | | **O(N)** | 10 | 100 | 1000 | | **O(N log N)** | 30 | 60 | 9000 | | **O(N^2)** | 100 | 10000 | 1000000 | | **O(2^N)** | 1024 | 1.26e+29 | 1.07e+301 | | **O(N!)** | 3628800 | 9.3e+157 | 4.02e+2567 | ### Data Structure Operations Complexity | Data Structure | Access | Search | Insertion | Deletion | | ----------------------- | :-------: | :-------: | :-------: | :-------: | | **Array** | 1 | n | n | n | | **Stack** | n | n | 1 | 1 | | **Queue** | n | n | 1 | 1 | | **Linked List** | n | n | 1 | 1 | | **Hash Table** | - | n | n | n | | **Binary Search Tree** | n | n | n | n | | **B-Tree** | log(n) | log(n) | log(n) | log(n) | | **Red-Black Tree** | log(n) | log(n) | log(n) | log(n) | | **AVL Tree** | log(n) | log(n) | log(n) | log(n) | ### Array Sorting Algorithms Complexity | Name | Best | Average | Worst | Memory | Stable | | --------------------- | :-------: | :-------: | :-----------: | :-------: | :-------: | | **Bubble sort** | n | n^2 | n^2 | 1 | Yes | | **Insertion sort** | n | n^2 | n^2 | 1 | Yes | | **Selection sort** | n^2 | n^2 | n^2 | 1 | No | | **Heap sort** | n log(n) | n log(n) | n log(n) | 1 | No | | **Merge sort** | n log(n) | n log(n) | n log(n) | n | Yes | | **Quick sort** | n log(n) | n log(n) | n^2 | log(n) | No | | **Shell sort** | n log(n) | depends on gap sequence | n (log(n))^2 | 1 | No |