题目描述：
Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm?
Hint:
Expected runtime complexity is in O(log n) and the input is sorted.
题目大意：
H-Index的延伸：如果引用数组是递增有序的，你应该怎样优化算法？
提示：
期望运行时间复杂度为O ...