[Leetcode/Graph (In-Degree/Out-Degree)] 997. Find the Town Judge

class Solution:
    def findJudge(self, n: int, trust: List[List[int]]) -> int:
        # If there's only one person and no trust relationships, that person is the judge
        if n == 1 and not trust:
            return 1
        
        # Initialize trust counts
        trust_scores = [0] * (n+1)

        for a,b in trust:
            trust_scores[a] -= 1 # a trusts someone → cannot be the judge
            trust_scores[b] += 1 # b is trusted → potential to be the judge

        # The judge should be trusted by n - 1 people and trust no one
        for i in range(1, n+1):
            if trust_scores[i] == n-1:
                return i
                
        return -1