[leetcode] 274. H-Index

原创

是念 2022-08-11 17:25:36 博主文章分类：leetcode ©著作权

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Description

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.

分析

题目的意思是：给出一个研究者的引用数组，算出这位研究者的H-index。

这个指数是用来衡量研究人员的学术水平的质数，定义为一个人的学术文章有n篇分别被引用了n次，那么H指数就是n。而且wiki上直接给出了算法，可以按照如下方法确定某人的H指数：
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。

代码

class Solution {
public:
    int hIndex(vector<int>& citations) {
        int n=citations.size();
        sort(citations.begin(),citations.end(),greater<int>());
        for(int i=0;i<n;i++){
            if(i>=citations[i]) return i;
        }
        return n;
    }
};