README_EN.md

997. Find the Town Judge

Description

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:

<li>The town judge trusts nobody.</li>

<li>Everybody (except for the town judge) trusts the town judge.</li>

<li>There is exactly one person that satisfies properties 1 and 2.</li>

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:

<li><code>1 &lt;= N &lt;= 1000</code></li>

<li><code>trust.length &lt;= 10000</code></li>

<li><code>trust[i]</code> are all different</li>

<li><code>trust[i][0] != trust[i][1]</code></li>

<li><code>1 &lt;= trust[i][0], trust[i][1] &lt;= N</code></li>

Solutions

Python3

Java

...