C++

1class Solution {
2  public:
3    int findJudge(int n, vector<vector<int>>& trust) {
4      vector<int> count(n+1, 0);
5      for(auto & t : trust) {
6        --count[t[0]]; // outbound
7        ++count[t[1]]; // inbound
8      }
9
10      for(int i=1; i<=n; ++i) {
11        if(count[i] == n-1) 
12          return i;   
13      }
14
15      return -1;
16    }
17};