Diagonal Difference - Problem from HackerRank

Problem Statement:

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.

Constraints

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

Note: |x| is absolute value function

Problem Solution using python 2:

n = input()

m =n

matrix =[]

while n:

    matrix.append(map(int, raw_input().split()[:m]))

    n -=1

primarydiagonal = [matrix[i][i] for i in range(len(matrix))]

secondarydiagonal = [matrix[i][len(matrix)-1-i] for i in range(len(matrix))]

#print sum(primarydiagonal), sum(secondarydiagonal)

print abs(sum(primarydiagonal) - sum(secondarydiagonal))