Absolute Difference of Diagonal Sums | Dataford Interview Questions

Workiva's reporting surfaces may represent a square set of aligned values as a matrix. Given a square matrix of integers, calculate the absolute difference between the sum of its primary diagonal and the sum of its secondary diagonal.

The primary diagonal runs from the top-left corner to the bottom-right corner. The secondary diagonal runs from the top-right corner to the bottom-left corner.

Formal Specification

Implement diagonal_difference(matrix), where matrix is a non-empty n x n list of lists of integers. Return a single non-negative integer equal to abs(primary_sum - secondary_sum).

You may count the center cell in both diagonal sums when n is odd. It appears in both sums, so it does not affect their difference.

Constraints

1 <= n <= 1,000
matrix contains exactly n rows and n integers per row
-10^9 <= matrix[i][j] <= 10^9
The matrix is non-empty and square

Function Signature

def diagonal_difference(matrix):

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