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 โ h papers have no more than h citations each."
Example:
Input: citations = [3,0,6,1,5]
Output: 3
Explanation:
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[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.
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Note: If there are several possible values for h, the maximum one is taken as the h-index.