最大最小值问题，应该是对总共的论文数作二分答案，但是昨天周赛写了对最高引用次数作二分的代码，懒得再写了。。

class Solution:
    def hIndex(self, citations: List[int]) -> int:
        if len(citations) == 0:
            return 0
        l, r = 0, citations[-1]
        ans = []
        while l < r:
            mid = (l + r) >> 1
            t = len(citations) - bisect_left(citations, mid)
            if t >= mid:
                l = mid + 1
            if t < mid:
                r = mid
                
        t = len(citations) - bisect_left(citations, r)
        
        return r if t >= r else l - 1