Practice Matrix Diagonal Sum
Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.
Problem Statement
Given a square matrix mat, return the sum of the matrix diagonals. Only include the sum of all the elements on the primary diagonal and all the elements on the secondary diagonal that are not part of the primary diagonal.
Source: Matrix Diagonal Sum on LeetCode. Use the original task for its coding environment and submissions.
Examples
# Example 1
Input
mat = [[1,2,3], [4,5,6], [7,8,9]]
Output
25
# Example 2
Input
mat = [[1,1,1,1], [1,1,1,1], [1,1,1,1], [1,1,1,1]]
Output
8
# Example 3
Input
mat = [[5]]
Output
5
Constraints
n == mat.length == mat[i].length
1 <= n <= 100
1 <= mat[i][j] <= 100
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