[leetcode] 324. Wiggle Sort II @ python

原题

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

Example 1:

Input: nums = [1, 5, 1, 1, 6, 4]
Output: One possible answer is [1, 4, 1, 5, 1, 6].
Example 2:

Input: nums = [1, 3, 2, 2, 3, 1]
Output: 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?

解法

将nums升序排列, 分为左右两边, 左右两边倒序然后交叉排列即可.

代码

class Solution(object):
    def wiggleSort(self, nums):
        """
        :type nums: List[int]
        :rtype: None Do not return anything, modify nums in-place instead.
        """
        nums.sort()
        mid = (len(nums)+1)//2
        left, right = nums[:mid], nums[mid:]
        nums[::2] = left[::-1]
        nums[1::2] = right[::-1]