#2435
Paths in Matrix Whose Sum Is Divisible by K
expert · 1210 · lc hard +32 · verified · 58.7% accepted · 1,340 likes · top 55%
Description
You are given a 0-indexed m x n integer matrix grid and an integer k. Starting at (0, 0), you want to reach (m - 1, n - 1) by moving only right or down.
Count the number of paths whose element sum is divisible by k. Return the result modulo 109 + 7.
Example 1:
Input: grid = [[5,2,4],[3,0,5],[0,7,2]], k = 3
Output: 2
Explanation: There are two paths where the sum of the elements on the path is divisible by k.
The first path highlighted in red has a sum of 5 + 2 + 4 + 5 + 2 = 18 which is divisible by 3.
The second path highlighted in blue has a sum of 5 + 3 + 0 + 5 + 2 = 15 which is divisible by 3.
Example 2:
Input: grid = [[0,0]], k = 5
Output: 1
Explanation: The path highlighted in red has a sum of 0 + 0 = 0 which is divisible by 5.
Example 3:
Input: grid = [[7,3,4,9],[2,3,6,2],[2,3,7,0]], k = 1
Output: 10
Explanation: Every integer is divisible by 1 so the sum of the elements on every possible path is divisible by k.
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