class Solution {
public:
    int subarraySum(vector<int>& array, int k) {
        unordered_map<int, int> sumToCount = {{0, 1}};
        int sum = 0;
        int sumCount = 0;

        for (auto& element: array) {
            sum += element;
            sumCount += sumToCount[sum - k];
            sumToCount[sum]++;
        }
        return sumCount;
    }
};