c_cpp 454. 4Sum II-中 - 2018.9.20

Posted 2021-05-14

class Solution {
public:
    int fourSumCount(vector<int>& A, vector<int>& B, vector<int>& C, vector<int>& D) {
        map<int, int> intMap_1;
        map<int, int> intMap_2;
        int re;
        for (int i = 0; i < A.size(); i++) {
            for (int j = 0; j < A.size(); j++) {
                intMap_1[A[i]+B[j]] += 1;
                intMap_2[C[i]+B[j]] += 1;
            }
        }f
        for (auto i : intMap_1) {
            re += i.second * intMap_2[-1*i.first];
        }
        return re;
    }
};