add diagonal_difference code in Udemy

[NeilSenEasow]

Problem: Diagonal Difference

Description:

The task is to calculate the absolute difference between the sums of a square matrix's two diagonals:

1. Primary Diagonal: The diagonal that runs from the top-left to the bottom-right of the matrix.
2. Secondary Diagonal: The diagonal that runs from the top-right to the bottom-left of the matrix.

You are given a n x n matrix (where n is the number of rows and columns), and you need to find the absolute difference between the sums of the primary and secondary diagonals.

Input:

• The first line contains an integer n, which represents the number of rows and columns of the matrix.
• The next n lines each contain n space-separated integers representing the matrix elements.

Output:

• Output a single integer: the absolute difference between the sums of the primary and secondary diagonals.

Example:

Input:

3
11 2 4
4 5 6
10 8 -12

Output:

15

Explanation:

• The primary diagonal elements are: 11, 5, -12. Sum = 4.
• The secondary diagonal elements are: 4, 5, 10. Sum = 19.
• The absolute difference between the sums is |4 - 19| = 15.

---

This explanation should make it clear what the problem is about and how to solve it. Add this description as comments at the top of your solution file (diagonal-difference.py), or include it in the pull request description. Here's how the comments could look:

# Problem: Diagonal Difference
# Description:
# Given a square matrix, calculate the absolute difference between the sums of its diagonals.
#
# Input:
# - The first line contains an integer n, the number of rows and columns.
# - The next n lines each contain n space-separated integers representing the matrix.
#
# Output:
# - Output a single integer, the absolute difference between the sums of the primary and secondary diagonals.
#
# Example:
# Input:
# 3
# 11 2 4
# 4 5 6
# 10 8 -12
# Output:
# 15

[welcome]

I can tell this is your first pull request! Thank you I'm so honored. 🎉🎉🎉
I'll take a look at it ASAP!