human
I found an interesting problem on https://leetcode.com/problems/matrix-diagonal-sum/:
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.
 
Example 1:

Input: mat = [[1,2,3],
              [4,5,6],
              [7,8,9]]
Output: 25
Explanation: Diagonals sum: 1 + 5 + 9 + 3 + 7 = 25
Notice that element mat[1][1] = 5 is counted only once.

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

I tried it in Python, but could not do it. Can you solve it?

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Write me a the Python program you requested?
assistant
#Here is the Python program you requested.

class Solution:
    def diagonalSum(self, mat: List[List[int]]) -> int:
        rows = len(mat)
        columns = len(mat[0])
        sum_ = 0
        for r, c1, c2 in zip(list(range(rows)), list(range(columns)), list(range(columns - 1, -1, -1))):
            sum_ += mat[r][c1]
            if c1 != c2:
                sum_ += mat[r][c2]
        return sum_