Leetcode-274题:H-Index

题目

Given an array of citations (each citation is a non-negative integer) of a researcher, write a function to compute the researcher's h-index.

According to the definition of h-index on Wikipedia: "A scientist has index h if h of his/her N papers have at least h citations each, and the other N − h papers have no more than h citations each."

For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5 papers in total and each of them had received 3, 0, 6, 1, 5 citations respectively. Since the researcher has 3 papers with at least 3 citations each and the remaining two with no more than 3 citations each, his h-index is 3.

代码

class Solution(object):
    def hIndex(self, citations):
        """
        :type citations: List[int]
        :rtype: int
        """

        if citations==None or len(citations)==0:
            return 0
        citations.sort()
        n = len(citations)
        h_index = 0
        for i in range(n-1, -1, -1):
            if n - i >= citations[i]:
                if citations[i] > h_index:
                    h_index = citations[i]
            else:
                if n - i > h_index:
                    h_index = n-i
        return h_index