In a town, there are `N`

people labelled 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 `trust`

, an array of pairs `trust[i] = [a, b]`

representing that the person labelled `a`

trusts the person labelled `b`

.

If the town judge exists and can be identified, return the label of the town judge. Otherwise, return `-1`

.

**Example 1:**

Input:N = 2, trust = [[1,2]]Output:2

**Example 2:**

Input:N = 3, trust = [[1,3],[2,3]]Output:3

**Example 3:**

Input:N = 3, trust = [[1,3],[2,3],[3,1]]Output:-1

**Example 4:**

Input:N = 3, trust = [[1,2],[2,3]]Output:-1

**Example 5:**

Input:N = 4, trust = [[1,3],[1,4],[2,3],[2,4],[4,3]]Output:3

**Note:**

`1 <= N <= 1000`

`trust.length <= 10000`

`trust[i]`

are all different`trust[i][0] != trust[i][1]`

`1 <= trust[i][0], trust[i][1] <= N`

## Solution

public class Solution { public int FindJudge(int N, int[][] trust) { int[] count = new int[N+1]; foreach(int[] t in trust) { count[t[0]]--; count[t[1]]++; } for(int i=1;i<=N;i++) { if(count[i] == N-1) return i; } return -1; } }

Time Complexity: O(n) + O(n) => O(n)

Space Complexity: O(n)