Find the town judge

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] = [a_i, b_i] representing that the person labeled a_i trusts the person labeled b_i .

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

Input Format

First Parameter : n, no of people in row
Second Parameter: trust, 2d array representing trust between people

Output Format

Return label of town judge if exists else return -1.

Example 1:

Input: 
2  
1 2
1 2
Output: 
2
explanation: 1 2 represents the size of the matrix trust.

Example 2:

Input: 
3  
2 2
1 3
2 3
Output: 
3
explanation: 2 2 represents the size of the matrix trust.

Example 3:

Input: 
3  
3 2
1 3
2 3
3 1
Output: 
-1
explanation: 3 2 represents the size of the matrix trust.

Constraints :

• 1 <= n <= 10³.
• 0 <= trust.length (number of rows) <= 10⁴.
• trust[i].length == 2.
• All the pairs of trust are unique.
• *a_i != b_i *
• 1 <= a_i , b_i <= n .
• Expected Time Complexity: O(n)
• Expected Space Complexity: O(n).