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106 lines
5.9 KiB
Markdown
106 lines
5.9 KiB
Markdown
# JavaScript Algorithms and Data Structures
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[![Build Status](https://travis-ci.org/trekhleb/javascript-algorithms.svg?branch=master)](https://travis-ci.org/trekhleb/javascript-algorithms)
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[![codecov](https://codecov.io/gh/trekhleb/javascript-algorithms/branch/master/graph/badge.svg)](https://codecov.io/gh/trekhleb/javascript-algorithms)
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## Code Examples
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### Data Structures
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1. [Linked List](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/linked-list)
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2. [Queue](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/queue)
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3. [Stack](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/stack)
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4. [Hash Table](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/hash-table)
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5. [Heap](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/heap)
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6. [Priority Queue](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/priority-queue)
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7. [Trie](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/trie)
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8. [Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree)
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* [Binary Search Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree/binary-search-tree)
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* [AVL Tree](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/tree/avl-tree)
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9. [Graph](https://github.com/trekhleb/javascript-algorithms/tree/master/src/data-structures/graph)
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### Algorithms
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* Math
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* [Fibonacci Number](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/fibonacci)
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* [Cartesian Product](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/cartesian-product)
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* [Power Set](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/math/power-set)
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* String
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* [String Permutations](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/string/permutations)
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* Graph
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* [Depth-First Search (DFS)](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/graph/depth-first-search)
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* [Breadth-First Search (BFS)](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/graph/breadth-first-search)
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* Sorting
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* [Bubble Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/bubble-sort)
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* [Selection Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/selection-sort)
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* [Insertion Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/insertion-sort)
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## Running Tests
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**Run all tests**
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```
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npm test
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```
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**Run tests by name**
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```
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npm test -- -t 'LinkedList'
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```
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## Playground
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You may play with data-structures and algorithms in `./src/playground/playground.js` file and write
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tests for it in `./src/playground/__test__/playground.test.js`.
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Then just simply run the following command to test if your playground code works as expected:
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```
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npm test -- -t 'playground'
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```
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## Useful links
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* [Data Structures and Algorithms on YouTube](https://www.youtube.com/playlist?list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8)
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* Algorithms
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* Dynamic Programming
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* [Introduction to Dynamic Programming 1](https://www.hackerearth.com/practice/algorithms/dynamic-programming/introduction-to-dynamic-programming-1/tutorial/)
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## Useful Information
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### Big O Notation
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Order of growth of algorithms specified in Big O notation.
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![Big O graphs](https://github.com/trekhleb/javascript-algorithms/blob/master/assets/big-o-graph.png)
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Source: [Big O Cheat Sheet](http://bigocheatsheet.com/).
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Below is the list of some of the most used Big O notations and their performance comparisons against different sizes of the input data.
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| Big O Notation | Computations for 10 elements | Computations for 100 elements | Computations for 1000 elements |
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| -------------- | ---------------------------- | ----------------------------- | ------------------------------- |
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| **O(1)** | 1 | 1 | 1 |
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| **O(log N)** | 3 | 6 | 9 |
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| **O(N)** | 10 | 100 | 1000 |
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| **O(N log N)** | 30 | 60 | 9000 |
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| **O(N^2)** | 100 | 10000 | 1000000 |
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| **O(2^N)** | 1024 | 1.26e+29 | 1.07e+301 |
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| **O(N!)** | 3628800 | 9.3e+157 | 4.02e+2567 |
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### Common Data Structure Operations
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![Common Data Structure Operations](https://github.com/trekhleb/javascript-algorithms/blob/master/assets/big-o-data-structures.png)
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Source: [Big O Cheat Sheet](http://bigocheatsheet.com/).
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### Array Sorting Algorithms Complexity
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| Name | Best | Average | Worst | Memory | Stable |
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| --------------------- | :-------: | :-------: | :-------: | :-------: | :-------: |
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| **Bubble sort** | n | n^2 | n^2 | 1 | Yes |
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| **Insertion sort** | n | n^2 | n^2 | 1 | Yes |
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| **Selection sort** | n^2 | n^2 | n^2 | 1 | No |
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| **Heap sort** | n log(n) | n log(n) | n log(n) | 1 | No |
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| **Merge sort** | n log(n) | n log(n) | n log(n) | n | Yes |
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| **Quick sort** | n log(n) | n log(n) | n^2 | log(n) | No |
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| **Radix sort** | nk | nk | nk | n + k | |
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| **Bucket sort** | n + k | n + k | n^2 | n | |
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