#1314

Matrix Block Sum

pupil · 490 · lc medium +27 · verified · 76.4% accepted · 2,505 likes · top 87%

Description

Given an m x n integer matrix mat and an integer k, build and return a result matrix answer of the same dimensions where answer[i][j] is the sum of every valid entry mat[r][c] satisfying:

- i - k <= r <= i + k,

- j - k <= c <= j + k, and

- (r, c) lies within the matrix bounds.

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]]

Code

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class Solution:
    def matrixBlockSum(self, mat: List[List[int]], k: int) -> List[List[int]]:

class Solution:
    def matrixBlockSum(self, mat: List[List[int]], k: int) -> List[List[int]]: