JavaScript Algorithms and Data Structures

Code Examples

Data Structures

1. Linked List
2. Queue
3. Stack
4. Hash Table
5. Heap
6. Priority Queue
7. Trie
8. Tree
   • Binary Search 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

Algorithms

• Math
  • Fibonacci Number
  • Cartesian Product
  • Power Set
  • Primality Test (trial division)
  • Euclidean Algorithm - calculate the greatest common divisor (GCD)
  • Fisher–Yates Shuffle - random permutation of a finite sequence
  • Collatz Conjecture algorithm
  • Greatest Difference
  • Least Common Multiple
  • Newton's square
  • Shannon Entropy
• String
  • String Permutations
  • Combination
  • Minimum Edit distance (Levenshtein Distance)
  • Hamming
  • Huffman
  • Knuth Morris Pratt
  • Longest common subsequence
  • longest common substring
  • Rabin Karp
• Search
  • Binary Search
• Sorting
  • Bubble Sort
  • Selection Sort
  • Insertion Sort
  • Heap Sort
  • Merge Sort
  • Quicksort
  • Shellsort
• Graph
  • Depth-First Search (DFS)
  • Breadth-First Search (BFS)
  • 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
• Algorithms
  • Dynamic Programming
    • Introduction to Dynamic Programming 1

Useful Information

Big O Notation

Order of growth of algorithms specified in Big O notation.

Source: Big O Cheat Sheet.

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