题目：

题解：

class Solution:
    def hIndex(self, citations: List[int]) -> int:
        n = len(citations)
        left = 0; right = n - 1
        while left <= right:
            mid = left + (right - left) // 2
            if citations[mid] >= n - mid:
                right = mid - 1
            else:
                left = mid + 1
        return n - left