类别归档：LeetCode

题目描述：

Given an unsorted integer array, find the first missing positive integer.

For example,
Given [1,2,0] return 3,
and [3,4,-1,1] return 2.

Your algorithm should run in O(n) time and uses constant space.

题目大意：

给定一个未经排序的数组，寻找第一个缺失的正整数。

例如，
给定 [1,2,0] 返回3，
给定 ...

题目描述：

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n.

For example, given n = 12, return 3 because 12 = 4 + ...

题目描述：

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions ...

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(log n)，并且输入是递增有序的。

解题思路：

二分法（Binary ...

题目描述：

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 ...