997. Find the Town Judge

class Solution {
public:
    int findJudge(int n,vector<vector<int>>& trust){        
        vector<int> ans(n+1,0);
        for(auto &it:trust){
            ans[it[0]]--;
            ans[it[1]]++;
        }
        for(int i=1;i<=n;i++){
            if(ans[i]==n-1){
                return i;
            }
        }
        return -1;
    }
};