• Home
• com.github.javadev
• leetcode-in-java
• 1.17
• source code
• readme.md

×

Project download

Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance.
Project price only 1 $

You can buy this project and download/modify it how often you want.

g1501_1600.s1572_matrix_diagonal_sum.readme.md Maven / Gradle / Ivy

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:**

![](https://assets.leetcode.com/uploads/2020/08/14/sample_1911.png)

**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`