LeetCode Problem
275. H-Index II
Link to LeetCode
Given an array of integers citations where citations[i] is the number of citations a researcher received for their ith paper and citations is sorted in non-descending order, return the researcher's h-index.
According to the definition of h-index on Wikipedia: The h-index is defined as the maximum value of h such that the given researcher has published at least h papers that have each been cited at least h times.
You must write an algorithm that runs in logarithmic time.
Example 1:
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, their h-index is 3.
Example 2:
Input: citations = [1,2,100]
Output: 2
int hIndex(int[] citations) {
int len = citations.length;
if (len == 0) {
return 0;
}
if (len == 1) {
if (citations[0] == 0) {
return 0;
} else {
return 1;
}
}
int i = 0;
int j = len - 1;
while (i < j) {
int m = i + (j - i + 1) / 2;
if (citations[m] > len - m) {
j = m - 1;
} else {
i = m;
}
}
if (citations[j] > len - j) {
return len;
}
if (citations[j] == len - j) {
return len - j;
} else {
return len - j - 1;
}
}