Source code are the collections of coding questions and their source code. You will find the download link at the bottom of each page.

#### Autocomplete with trie (3 solutions) – Code

Autocomplete is a feature that search box returns the suggestions based on what you have typed. Autocomplete with trie provides ...

#### Depth first search in matrix using recursion

An adjacency matrix is a 2d array representing a graph. The nodes are the headings for the rows and columns ...

#### Shortest path and 2nd shortest path using Dijkstra – code

Dijkstra's algorithm is an algorithm to find the shortest paths between vertices in a graph. It uses greedy technique by ...

#### Shortest path from source to destination in matrix – Code

Shortest path in matrix is to find the shortest distance from the the source to the destination. As you know, ...

#### Huffman coding and decoding – Step by step

What is huffman coding? Huffman coding is an algorithm to generate the binary code based on the frequencies of corresponding ...

#### Build hierarchy tree – Code

Build hierarchy tree reads employee data and build a corporation hierarchy tree from the list. HashMap plays important role to ...

#### Detect cycle and remove cycle in directed graph

A graph is a data structure that consists of a set of nodes (vertices) connected by edges. A graph is ...

#### Find K closest points to origin (3 solutions) – Time complexity explained

The K closest problem is to find K closest points to the pointer(0,0) (it is called center or origin). The ...

#### Prefix to postfix (2 solutions) – stack and recursion

In mathematics expressions, there are infix, prefix and postfix notations. Infix notation is characterized by the placement of operators between ...

#### Modulo operation and circular array

The modulo operation returns the remainder of one number divided by another. Modulo operator is a arithmetical operator, represented as ...