class Solution(object):
    def moveZeroes(self, nums):
        """
        :type nums: List[int]
        :rtype: None Do not return anything, modify nums in-place instead.
        """
        pos = 0
        for i in range(len(nums)):
            if nums[i] != 0 :
                nums[pos] = nums[i]
                pos += 1
        nums[pos:] = [0]*len(nums[pos:])

def moveZeros(nums):
    j = 0   # 记录非零元素应该换到第几个位置
    for i in range(len(nums)):
        if nums[i] != 0:
            nums[j], nums[i] = nums[i], nums[j]
            j += 1
    return nums
print(moveZeros([1,0,1,0,3,12]))