Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm?
Solution:
here we use binary search
inspired from sorting method c[i] < i+1;
when citations c is in ascending order, the idea is find the minimum index c[i] >= len(c) -i
l = 0 h = len(citations)-1 while (l <= h): mid = (l+h)/2 if citations[mid] == len(citations)-mid: return len(citations)-mid elif citations[mid] < len(citations)-mid: l = mid+1 else: h = mid-1 return len(citations)-l
[Leetcode] Binary search--275 H-Index
原文：http://www.cnblogs.com/anxin6699/p/6978068.html
