Formatted question description: https://leetcode.ca/all/275.html
275 H-Index II 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 citations is now guaranteed to be sorted in ascending order. Could you solve it in logarithmic time complexity?
First initialize left and right to 0 and len-1, then take the middle value mid, compare citations[mid] with len-mid,
- If the former is big, right moves before mid
- On the contrary, right moves after mid
The loop condition is left<=right, and finally returns