diagonal_difference.py

"""
Given a square matrix of size , calculate the absolute difference between the sums of its diagonals.

Input Format

The first line contains a single integer, .
The next  lines denote the matrix's rows, with each line containing space-separated integers describing the columns.

Output Format

Print the absolute difference between the two sums of the matrix's diagonals as a single integer.

Sample Input

3
11 2 4
4 5 6
10 8 -12
Sample Output

15
Explanation

The primary diagonal is:
11
      5
            -12

Sum across the primary diagonal: 11 + 5 - 12 = 4

The secondary diagonal is:
            4
      5
10
Sum across the secondary diagonal: 4 + 5 + 10 = 19
Difference: |4 - 19| = 15

"""

# 1 2 3 4
# 5 6 7 8
# 9 1 2 3
# 4 5 6 7

n = 3
rows = [[11, 2, 4],
        [4, 5, 6],
        [10, 8, -12]]


def row_summation(rows):
    on_row = 0
    _sum = 0
    for row in rows:
        _sum += row[on_row]
        on_row += 1
    return _sum


difference = abs(row_summation(rows) - row_summation(rows[::-1]))
print(difference)