Given an array of citations sorted in ascending order (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 = [0,1,3,5,6]
Output: 3
Explanation: [0,1,3,5,6] means the researcher has 5 papers in total and each of them had
received 0, 1, 3, 5, 6 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.
Follow up:
- This is a follow up problem to H-Index, where
citationsis now guaranteed to be sorted in ascending order. - Could you solve it in logarithmic time complexity?
Runtime: 32 ms, faster than 54.70% of C++ online submissions for H-Index II.
#include <vector>
using namespace std;
class Solution {
public:
int hIndex(vector<int>& citations) {
int mid = 0, left = 0, right = citations.size();
while(left < right){
mid = left + (right - left) / 2;
if(citations.size() - mid > citations[mid] ){
left = mid+1;
}else right = mid;
}
return citations.size() - left;
}
};