Find the Town Judge.cpp

/* 
    Solution by Rahul Surana
    
    ***********************************************************


In a town, there are n people labeled from 1 to n. There is a rumor that one of these people is secretly the town judge.

If the town judge exists, then:

The town judge trusts nobody.
Everybody (except for the town judge) trusts the town judge.
There is exactly one person that satisfies properties 1 and 2.
You are given an array trust where trust[i] = [ai, bi] representing that the person labeled ai trusts the person labeled bi.

Return the label of the town judge if the town judge exists and can be identified, or return -1 otherwise.


    ***********************************************************
*/


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