Find the Town Judge.java

/* 
    Solution by Rahul Surana
    
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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. 
If a trust relationship does not exist in trust array, then such a trust relationship does not exist.

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, int[][] trust) {
        int[] f = new int[n+1];
        Arrays.fill(f,0);
        for(int[] x: trust){
            f[x[0]]--;
            f[x[1]]++;
        } 
        for(int i = 1; i <= n; i++){
            if(f[i] == n-1) return i;
        }
        return -1;
    }
}