h-index.py

# -*- coding:utf-8 -*-


# 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."
#
# Example:
#
#
# Input: citations = [3,0,6,1,5]
# Output: 3 
# Explanation: [3,0,6,1,5] 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, her 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
        """
        citations.sort(reverse=True)
        res = [0]
        for i, v in enumerate(citations):
            if i+1 <= v:
                res.append(i+1)
        
        return res.pop()