Question

Code

# The knows API is already defined for you.
# return a bool, whether a knows b
# def knows(a: int, b: int) -> bool:

class Solution:
    def findCelebrity(self, n: int) -> int:
        
        celeb = 0

        for i in range(1, n):
            if knows(celeb, i):
                celeb = i

        if self.verify(celeb, n):
            return celeb
        else:
            return -1

    def verify(self, celeb, n):

        for i in range(n):
            if i == celeb:
                continue
            
            if knows(celeb, i) or not knows(i, celeb):
                return False

        return True