# Hackerrank - Diagonal Difference Solution

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

For example, the square matrix is shown below:

```
1 2 3
4 5 6
9 8 9
```

The left-to-right diagonal = . The right to left diagonal = . Their absolute difference is .

**Function description**

Complete the function in the editor below. It must return an integer representing the absolute diagonal difference.

diagonalDifference takes the following parameter:

*arr*: an array of integers .

**Input Format**

The first line contains a single integer, , the number of rows and columns in the matrix .

Each of the next lines describes a row, , and consists of space-separated integers .

**Constraints**

**Output Format**

Print the absolute difference between the sums of the matrix's two 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 the absolute value of x

### Solution in python

```
#!/bin/python3
import math
import os
import random
import re
import sys
def diagonalDifference(nums):
diagonal1 = 0
diagonal2 = 0
for i in range(len(nums)):
diagonal1+= nums[i][i]
diagonal2+= nums[i][len(nums)-i-1]
return (abs(diagonal1- diagonal2))
if __name__ == '__main__':
fptr = open(os.environ['OUTPUT_PATH'], 'w')
n = int(input().strip())
arr = []
for _ in range(n):
arr.append(list(map(int, input().rstrip().split())))
result = diagonalDifference(arr)
fptr.write(str(result) + '\n')
fptr.close()
```