LeetCode-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.

1、将其发表的所有SCI论文按被引次数从高到低排序；2、从前往后查找排序后的列表，直到某篇论文的序号大于该论文被引次数。所得序号减一即为H指数。

class Solution {
    public int hIndex(int[] citations) {
        int size = citations.length;
        if(size<=0)
            return 0;
        Arrays.sort(citations);
        int count = 0;
        for(int i = size-1;i>=0;i--){
            if(count>=citations[i])
                return Math.max(count,citations[i]);
            count++;
        }
        return count;
    }
}