283. Move Zeroes

Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements.

Example:

Input: [0,1,0,3,12]
Output: [1,3,12,0,0]
Note:

You must do this in-place without making a copy of the array.
Minimize the total number of operations.

解题思路：
双指针法，慢指针停留在 0 ，快指针寻找非零元素进行交换。

class Solution(object):
    def moveZeroes(self, nums):
        """
        :type nums: List[int]
        :rtype: None Do not return anything, modify nums in-place instead.
        """
        i, j = 0, 0
        while j < len(nums):
            if nums[i] <> 0 and nums[j] <> 0:
                i += 1
            elif nums[i] == 0 and nums[j] <> 0:
                tt = nums[j]
                nums[j] = nums[i]
                nums[i] = tt
                i += 1
            j += 1
        return nums