*H-Index

Given an array of citations (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."

For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5 papers in total and each of them had received 3, 0, 6, 1, 5 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, his h-index is 3.

Note: If there are several possible values for h, the maximum one is taken as the h-index.

Hint:

  1. An easy approach is to sort the array first.
  2. What are the possible values of h-index?
  3. A faster approach is to use extra space.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases

 

 

 1 public class Solution {
 2     public int hIndex(int[] citations) {
 3         if (citations == null || citations.length == 0) return 0;
 4         Arrays.sort(citations);
 5         int len = citations.length;
 6         for (int i = 0; i < citations.length; i++) {
 7             if (len <= citations[i])
 8                 return len;
 9             else
10                 len--;
11         }
12         return len;
13     }
14 }

 

reference: https://leetcode.com/discuss/60791/simple-java-solution-with-sort

 

posted @ 2015-10-08 03:41  Hygeia  阅读(209)  评论(0)  编辑  收藏  举报