leetcode HIndex
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public class HIndex {
public static int solution(int[] citations){
/**
* citations: sorted arrays
*
* 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?
*/
int n = citations.length;
int left = 0;
int right = n;
while(left <= right){
int mid = (left+right) >> 1;
if (citations[mid] == n-mid){
return citations[mid];
}
else if (citations[mid] < n-mid){
left = mid+1;
}
else
right = mid-1;
}
return n-(right+1);
}
public static void main(String[] args){

}
}