Leetcode daily # 8.05.2023

[1572. Matrix Diagonal Sum]

8.05.2023

1572. Matrix Diagonal Sum easy

fun diagonalSum(mat: Array<IntArray>): Int =
    (0..mat.lastIndex).sumBy {
        mat[it][it] + mat[it][mat.lastIndex - it]
    }!! - if (mat.size % 2 == 0) 0 else mat[mat.size / 2][mat.size / 2]

blog post

Join me on Telegram

https://t.me/leetcode_daily_unstoppable/206

Intuition

Just do what is asked.

Approach

• avoid double counting of the center element

Complexity

• Time complexity:
  O(n)

• Space complexity:
  O(1)