版权声明：版权归个人所有，未经博主允许，禁止转载 https://blog.csdn.net/danspace1/article/details/88573109
原题
https://leetcode.com/problems/find-the-celebrity/
解法
首先遍历n个人, 找出可能的候选人cand, 根据名人的定义, 名人是所有人都认识他, 但他不认识别人. 所以, 当knowns(cand, i)为真时, cand需要更新为i, 根据题意, n个人中最多有一个名人, 那么遍历完之后的这个cand就是候选人. 再遍历n个人, 根据定义确定cand是否为名人.
Time: O(2*n)
Space: O(1)
代码
# The knows API is already defined for you.
# @param a, person a
# @param b, person b
# @return a boolean, whether a knows b
# def knows(a, b):
class Solution(object):
def findCelebrity(self, n):
"""
:type n: int
:rtype: int
"""
cand = 0
for i in range(1, n):
if knows(cand, i):
cand = i
for i in range(n):
if i != cand and (not knows(i, cand) or knows(cand, i)):
return -1
return cand