# GeetCode Hub

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:

1. The town judge trusts nobody.
2. Everybody (except for the town judge) trusts the town judge.
3. 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
```

Constraints:

• `1 <= n <= 1000`
• `0 <= trust.length <= 104`
• `trust[i].length == 2`
• `trust[i]` are all different
• `trust[i][0] != trust[i][1]`
• `1 <= trust[i][0], trust[i][1] <= n`

class Solution { public: int findJudge(int n, vector<vector<int>>& trust) { } };
Medium