Coding with Thong

Data Structures and Algorithms Diary

  • Dijkstra Algorithm in JavaScript, heap based fast implementation

    Let’s pick up from where we left off and revisit the problem Dijkstra algorithm aims to solve. Input: directed graph G = (V, E) in adjacency-list representation, a source vertex s ∈ V, a length le ≥ 0 for each e ∈ E. Output: the true shortest-path distance to every vertex v from the source…

  • Dijkstra’s Algorithm in JavaScript, slow implementation

    Dijkstra’s Algorithm is a handy tool for figuring out the shortest path in a connected directed graph where each connection has a non-negative weight. If you’re familiar with Prim’s Minimum Spanning Tree, despite having different goals, you’ll observe that both employ a greedy strategy to carefully select the optimal/smallest distance path step by step. Note:…

  • Priority queue min heap implementation in JavaScript

    Here’s what I’ve learned about the heap data structure. The invariant of the min/max heap is this: when represented in a binary tree, the parent node’s value is always smaller/bigger than or equal to its children. The root is always the smallest/biggest value of the heap when represented as a binary tree. The two most…

  • Graph data structure in JavaScript

    Here’s what I’ve learned about the graph data structure. Let’s start. We will represent the graph as an adjacency list, which is an object (or a hash table) that maps each vertex to an array of its adjacent vertices. This is a simple and efficient way to store the graph structure in JavaScript. To add…