leetcode 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.”

For example, given citations = [3, 0, 6, 1, 5], which 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, his h-index is 3.

Note: If there are several possible values for h, the maximum one is taken as the h-index.

这个直接根据H-Index的百科即可。

代码如下：

import java.util.Arrays;/* * https://baike.baidu.com/item/h-index/3991452?fr=aladdin * 参见H-Index的百科即可 * */class Solution{    public int hIndex(int[] citations)    {        if(citations==null || citations.length<=0)            return 0;        Arrays.sort(citations);        int maxH=0;        for(int i=citations.length-1;i>=0;i--)        {            int count=citations.length-i;            if(citations[i]>=count && count>maxH)                maxH=count;            else                break;        }        return maxH;    }}

下面是C++的做法，按照H-Index的含义去做即可，代码如下：

#include <iostream>#include <vector>#include <map>#include <set>#include <queue>#include <stack>#include <string>#include <algorithm>using namespace std;class Solution {public:    int hIndex(vector<int>& c)     {        sort(c.begin(),c.end());        int maxH = 0;        for (int i = c.size() - 1; i >= 0; i--)        {            int count = c.size() - i;            if (c[i] >= count && count > maxH)                maxH = count;        }        return maxH;    }};