Question

Formatted question description: https://leetcode.ca/all/274.html

 274	H-Index

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.



Algorithm

1. Sort all SCI papers published by him in descending order of the number of citations;
2. Search the sorted list from front to back until the serial number of a paper is greater than the number of times the paper has been cited.

The obtained serial number minus one is the H index

Java