Given a square matrix, calculate the absolute difference between the sums of its diagonals.
or example, the square matrix arr is shown below:
1 2 3
4 5 6
9 8 9
The left-to-right diagonal = 1 + 5 +9 = 15. The right to left diagonal = 3 + 5 + 9 = 17. Their absolute difference is |15 – 17| = 2.
Function description
Complete the DiagonalDifference function in the editor below.
diagonalDifference takes the following parameter:
- int arr[n][m]: an array of integers
Return
- int: the absolute diagonal difference
Input Format
The first line contains a single integer, n, the number of rows and columns in the square matrix arr.
Each of the next n lines describes a row, arr[i], and consists of n space-separated integers arr[i][j].
Constraints
- -100 <= arr[i][j] <= 100
Output Format
Return 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
Diagonal Difference Hacker Rank Solution:
Problem solution in C++ programming
int diagonalDifference(vector<vector<int>> arr) { size_t size = arr[0].size(); int sum{}; int i=0; for(const auto& vec : arr) sum+= (vec[size-1-i] - vec[i++]); return abs(sum); }
Problem solution in JavaScript programming
function diagonalDifference(arr) { // Write your code here let first_diagonal = 0, second_diagonal = 0 let len = arr.length - 1 for(let i=0; i<arr.length; i++){ first_diagonal += arr[i][i]; second_diagonal += arr[i][len-i]; } let res = first_diagonal - second_diagonal return Math.abs(res) }
Problem solution in Python programming
def diagonalDifference(arr): Write your code here first_diagonal = second_diagonal = 0 # Time: O(n) # Space: O(1) for i in range(len(arr)): first_diagonal += arr[i][i] second_diagonal += arr[i][len(arr) - 1 - i] return abs(first_diagonal - second_diagonal)
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