Given an unsorted array <code>nums</code>, reorder it such that <code>nums[0] < nums[1] > nums[2] < nums[3]...</code>.
Example:
(1) Given <code>nums = [1, 5, 1, 1, 6, 4]</code>, one possible answer is <code>[1, 4, 1, 5, 1, 6]</code>.
(2) Given <code>nums = [1, 3, 2, 2, 3, 1]</code>, one possible answer is <code>[2, 3, 1, 3, 1, 2]</code>.
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:
这道题给了我们一个无序数组,让我们排序成摆动数组,满足nums[0] < nums[1] > nums[2] < nums[3]...,并给了我们例子。我们可以先给数组排序,然后在做调整。调整的方法是找到数组的中间的数,相当于把有序数组从中间分成两部分,然后从前半段的末尾取一个,在从后半的末尾去一个,这样保证了第一个数小于第二个数,然后从前半段取倒数第二个,从后半段取倒数第二个,这保证了第二个数大于第三个数,且第三个数小于第四个数,以此类推直至都取完,参见代码如下:
解法一:
解法二: