3619: Count Islands With Total Value Divisible by K

Problem Statement

You are given an m x n matrix grid and a positive integer k. An island is a group of positive integers (representing land) that are 4-directionally connected (horizontally or vertically).

The total value of an island is the sum of the values of all cells in the island.

Return the number of islands with a total value divisible by k.

Example 1:

Input: grid = [[0,2,1,0,0],[0,5,0,0,5],[0,0,1,0,0],[0,1,4,7,0],[0,2,0,0,8]], k = 5

Output: 2

Explanation:

The grid contains four islands. The islands highlighted in blue have a total value that is divisible by 5, while the islands highlighted in red do not.

Example 2:

Input: grid = [[3,0,3,0], [0,3,0,3], [3,0,3,0]], k = 3

Output: 6

Explanation:

The grid contains six islands, each with a total value that is divisible by 3.

Constraints:

  • m == grid.length
  • n == grid[i].length
  • 1 <= m, n <= 1000
  • 1 <= m * n <= 105
  • 0 <= grid[i][j] <= 106
  • 1 <= k <= 106

Code Solution