Leetcode 997. 找到小镇的法官

class Solution {
public:
    int findJudge(int N, vector<vector<int>>& trust) {
        vector<unordered_set<int>> vc1(N+1);
        vector<unordered_set<int>> vc2(N+1);
        for(auto& m:trust){
            vc1[m[0]].insert(m[1]);//出
            vc2[m[1]].insert(m[0]);//入
        }

        int res = -1;
        for(int i=1;i <= N;i++){
            if(vc1[i].size()==0&&vc2[i].size()==(N-1)){
                res = i;
                break;
            }
        }
        return res;
    }
};

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