问题描述:
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 has5
papers in total and each of them had received3, 0, 6, 1, 5
citations respectively. Since the researcher has3
papers with at least3
citations each and the remaining two with no more than3
citations each, her h-index is3
.
Note: If there are several possible values for h, the maximum one is taken as the h-index.
解题思路:
首先要明白h-index的定义:
N篇论文中, 有h篇论文的引用至少为h;剩下的(N-h)篇论文的引用最多为h
我们不妨先给引用数组从高到低排序
然后从头开始遍历并且更新ret。
当ret>=当前值且<=下一个值的时候,就可以返回ret。
注意特例!!
当全为0的时候,需要返回0
代码:
class Solution { public: int hIndex(vector<int>& citations) { sort(citations.begin(), citations.end(), greater<int>()); if(citations.size() == 0 || citations[0] == 0) return 0; int ret = 0; int n = citations.size(); for(int i = 0; i < n; i++){ ret++; if(citations[i] >= ret && i + 1 < n && citations[i+1] <= ret) return ret; } return ret; } };