峰与谷

class Solution:
    def wiggleSort(self, nums: List[int]) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """
        for i in range(len(nums)-1):
            if nums[i]>nums[i+1]:

                if i%2==0:
                    nums[i],nums[i+1]=nums[i+1],nums[i]
            else:
                if i%2==1:
                    nums[i],nums[i+1]=nums[i+1],nums[i]