# Source Code

Source code are the collections of coding interview questions and their source code. Click the title you are interested, you will find the download link of the source code. Cannot find what you want? Please check out my github and my Java coding book.

#### Implement graph as adjacency list

A graph is a data structure that consists of a set of nodes connected by edges. Graphs are used to ...

#### Implement weighted graph as adjacency list

A graph is a data structure that consists of a set of nodes connected by edges. Graphs are used to ...

#### 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, ...

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

What is Dijkstra's algorithm? Dijkstra's algorithm is an algorithm to find the shortest paths between vertices in a graph. It ...

#### Build hierarchy tree – Code

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

#### 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 ...

#### 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 ...

#### 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 ...

#### 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 ...

#### 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 ...