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.

For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3, 12, 0, 0].

Note:

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

此题可以使用insert index来做，具体是设置一个idx，然后遍历数组，遇到不等于0的数组元素，复制给idx，然后idx++，具体代码如下：

public class Solution {

    public void moveZeroes(int[] nums) {

        int idx = 0;

        for(int i=0;i<nums.length;i++){

            if(nums[i]!=0){

                nums[idx++] = nums[i];

            }

        }

        for(int i=idx;i<nums.length;i++){

            nums[i] = 0;

        }

    }

}

283. Move Zeroes