Challenge: Find the longest substring present in an array!

Let be a two-dimensional square array of (any) characters, return the longest string of equal adjacent characters.

Input

B	B	D	A	D	E	F
B	X	C	D	D	J	K
H	Y	I	3	D	D	3
R	7	O	Ñ	G	D	2
W	N	S	P	E	0	D
A	9	C	D	D	E	F
B	X	D	D	D	J	K

Output

Result: D, D, D, D, D

It should return the string D, D, D, D, D because there is a diagonal of D of length 5 which is the longest.

Overview

The project was made in the C# programming language, it is a console application that uses .NET 5.0.

Inside the project you will find a file Input.txt where you can place the input array that the program will use.

In order to compile the application you will need:

1. Have .NET 5.0 installed.
2. Have Visual Studio 2019 or higher installed.