324. Wiggle Sort II

题目

Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]....

Example:

1. Given nums = [1, 5, 1, 1, 6, 4], one possible answer is [1, 4, 1, 5, 1, 6].
2. Given nums = [1, 3, 2, 2, 3, 1], one possible answer is [2, 3, 1, 3, 1, 2].

Note: You may assume all input has valid answer.

Follow Up: Can you do it in O(n) time and/or in-place with O(1) extra space?

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

解题思路

见程序注释