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