Leetcode 974. Subarray Sums Divisible by K

class Solution:
    def subarraysDivByK(self, nums: List[int], k: int) -> int:
        n = len(nums)
        count = 0
        stat = collections.defaultdict(int)
        stat[0] = 1
        total = 0
        for i in range(n):
            total += nums[i]
            remainder = total % k
            count += stat[remainder]
            stat[remainder] += 1
        return count