Leetcode 274. H-Index (Medium) (cpp)

Leetcode 274. H-Index (Medium) (cpp)

Tag: Hash Table, Sort

Difficulty: Medium

/*274. H-Index (Medium)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.Hint:An easy approach is to sort the array first.What are the possible values of h-index?A faster approach is to use extra space.*/class Solution {public:    int hIndex(vector<int>& citations) {        sort(citations.begin(), citations.end());        int _size = citations.size();        for (int i = 0; i < _size; i++) {            if (citations[i] >= _size - i) {                return _size - i;            }        }        return 0;    }};