Leetcode 974. And K divisible subarray prefix sum

Original link ：Leetcode 974. And can be K A subarray of integers

class Solution {
    
public:
    int subarraysDivByK(vector<int>& nums, int k) {
    
        unordered_map<int,int> mp;
        int tmp=0,res=0;
        for(int i=0;i<nums.size();i++)
        {
    
            tmp+=nums[i];
            int t=(tmp%k+k)%k;
            res+=mp[t];
            mp[t]++;
        }
        return mp[0]+res;
    }
};