283. Move Zeroes

问题描述：

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:

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

解题思路：

我们可以用两个变量来一起遍历。

新数组下标idx， 和原数组i

当nums[i] ！= 0的时候，令nums[idx] = nums[i]并且idx++

最后要把idx以及剩余位置填上0.

代码：

class Solution {
public:
    void moveZeroes(vector<int>& nums) {
        int idx = 0;
        for(int i = 0; i < nums.size(); i++){
            if(nums[i] != 0){
                nums[idx++] = nums[i];
            }
        }
        for(int i = idx; i < nums.size(); i++){
            nums[i] = 0;
        }
    }
};