275. H-Index II
Problem:
Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm?
Hint:
Expected runtime complexity is in O(log n) and the input is sorted.
Solutions:
public class Solution {
public int hIndex(int[] citations) {
if (citations.length == 0) {
return 0;
}
int left = 0, right = citations.length - 1;
while (left <= right) {
int mid = (left + right) / 2;
if (citations[mid] < citations.length - mid) {
left = mid + 1;
}
else {
right = mid - 1;
}
}
return citations.length - left;
}
}