H-Index

Can you solve this real interview question? H-Index - Given an array of integers citations where citations[i] is the number of citations a researcher received for their ith paper, return the researcher's h-index.

According to the definition of h-index on Wikipedia [https://en.wikipedia.org/wiki/H-index]: The h-index is defined as the maximum value of h such that the given researcher has published at least h papers that have each been cited at least h times.

 

Example 1:

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, their h-index is 3.

Example 2:

Input: citations = [1,3,1] Output: 1

Solution

class Solution:
    def hIndex(self, citations: List[int]) -> int:
        n = len(citations)
        citations.sort()

        for i,v in enumerate(citations):
            if n - i <= v:
                return n - i
        return 0