09 Sept 2026•Easy•Go / Python / TypeScript

Find the Town Judge

Find the person trusted by everyone else who trusts nobody.

Give each person one score for incoming trust and minus one for outgoing trust; the judge's final score is n minus one.

Complexity

O(n + t) time and O(n) space.

Solution files

Go•find-the-town-judge/solution.go

package main

func findJudge(n int, trust [][]int) int {
	score := make([]int, n+1)
	for _, relation := range trust {
		score[relation[0]]--
		score[relation[1]]++
	}
	for person := 1; person <= n; person++ {
		if score[person] == n-1 {
			return person
		}
	}
	return -1
}

Python•find-the-town-judge/solution.py

class Solution:
    def findJudge(self, n: int, trust: list[list[int]]) -> int:
        score = [0] * (n + 1)
        for source, target in trust: score[source] -= 1; score[target] += 1
        return next((person for person in range(1, n + 1) if score[person] == n - 1), -1)

TypeScript•find-the-town-judge/solution.ts

function findJudge(n: number, trust: number[][]): number {
  const score = new Array<number>(n + 1).fill(0);
  for (const [from, to] of trust) { score[from] -= 1; score[to] += 1; }
  for (let person = 1; person <= n; person += 1) if (score[person] === n - 1) return person;
  return -1;
}