g1501_1600.s1572_matrix_diagonal_sum

Class Solution

java.lang.Object

g1501_1600.s1572_matrix_diagonal_sum.Solution

public class Solution
extends Object

1572 - Matrix Diagonal Sum.

Easy

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

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	diagonalSum(int[][] mat)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

diagonalSum

public int diagonalSum(int[][] mat)