H-Index II

public class Solution {    public int hIndex(int[] citations) {        int n = citations.length;        if (n == 0) {            return 0;        }        int min = 0, max = n - 1;        while (min <= max) {            int mid = min + (max - min)/2;            if (citations[mid] >= n - mid) {                max = mid - 1;            } else {                min = mid + 1;            }        }        return n - min;    }}