Daily Archives: October 29, 2021

C# || How To Traverse Binary Tree Level Order Using C#

The following is a module with functions which demonstrates how to traverse binary tree level order using C#.


1. Level Order – Problem Statement

Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e., from left to right, level by level).

Example 1:

Example 1


Input: root = [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]

Example 2:


Input: root = [1]
Output: [[1]]

Example 3:


Input: root = []
Output: []


2. Level Order – Solution

The following is a solution which demonstrates how to traverse binary tree level order.

This solution uses Breadth First Search to explore items at each level.

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output for the example cases:


[[3],[9,20],[15,7]]
[[1]]
[]

C# || How To Determine When A Fresh Orange Becomes Rotten Using C#

The following is a module with functions which demonstrates how to determine when a fresh orange becomes rotten using C#.


1. Oranges Rotting – Problem Statement

You are given an m x n grid where each cell can have one of three values:

  • 0 representing an empty cell,
  • 1 representing a fresh orange, or
  • 2 representing a rotten orange.

Every minute, any fresh orange that is 4-directionally adjacent to a rotten orange becomes rotten.

Return the minimum number of minutes that must elapse until no cell has a fresh orange. If this is impossible, return -1.

Example 1:

Example 1


Input: grid = [[2,1,1],[1,1,0],[0,1,1]]
Output: 4

Example 2:


Input: grid = [[2,1,1],[0,1,1],[1,0,1]]
Output: -1
Explanation: The orange in the bottom left corner (row 2, column 0) is never rotten, because rotting only happens 4-directionally.

Example 3:


Input: grid = [[0,2]]
Output: 0
Explanation: Since there are already no fresh oranges at minute 0, the answer is just 0.


2. Oranges Rotting – Solution

The following is a solution which demonstrates how to determine when a fresh orange becomes rotten.

This solution uses Breadth First Search when looking for fresh cells to turn rotten.

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output for the example cases:


4
-1
0