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.

Note: If there are several possible values for h, the maximum one is taken as the h-index.


class Solution(object):
    def hIndex(self, citations):
        :type citations: List[int]
        :rtype: int
        N = len(citations)
        if (N == 0):
            return 0
        if (N == 1):
            return min(1, citations[0])


        for h in range(1, N):
            if(citations[h-1] >= h and citations[h] <= h):
                return h
        if(citations[N-1] >= N):
            return N
            return 0