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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. |
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If the town judge exists, then: |
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The town judge trusts nobody. |
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Everybody (except for the town judge) trusts the town judge. |
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There is exactly one person that satisfies properties 1 and 2. |
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You are given trust, an array of pairs trust[i] = [a, b] representing that the person labelled a trusts the person labelled b. |
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If the town judge exists and can be identified, return the label of the town judge. Otherwise, return -1. |
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Example 1: |
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Input: N = 2, trust = [[1,2]] |
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Output: 2 |
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Example 2: |
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Input: N = 3, trust = [[1,3],[2,3]] |
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Output: 3 |
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Example 3: |
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Input: N = 3, trust = [[1,3],[2,3],[3,1]] |
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Output: -1 |
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Example 4: |
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Input: N = 3, trust = [[1,2],[2,3]] |
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Output: -1 |
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Example 5: |
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Input: N = 4, trust = [[1,3],[1,4],[2,3],[2,4],[4,3]] |
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Output: 3 |
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Note: |
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1 <= N <= 1000 |
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trust.length <= 10000 |
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trust[i] are all different |
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trust[i][0] != trust[i][1] |
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1 <= trust[i][0], trust[i][1] <= N |
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