Class Solution


  • public class Solution
    extends Object
    1314 - Matrix Block Sum.

    Medium

    Given a m x n matrix mat and an integer k, return a matrix answer where each answer[i][j] is the sum of all elements mat[r][c] for:

    • i - k <= r <= i + k,
    • j - k <= c <= j + k, and
    • (r, c) is a valid position in the matrix.

    Example 1:

    Input: mat = [[1,2,3],[4,5,6],[7,8,9]], k = 1

    Output: [[12,21,16],[27,45,33],[24,39,28]]

    Example 2:

    Input: mat = [[1,2,3],[4,5,6],[7,8,9]], k = 2

    Output: [[45,45,45],[45,45,45],[45,45,45]]

    Constraints:

    • m == mat.length
    • n == mat[i].length
    • 1 <= m, n, k <= 100
    • 1 <= mat[i][j] <= 100
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • matrixBlockSum

        public int[][] matrixBlockSum​(int[][] mat,
                                      int k)