Sorry this is my first time coding on leetcode, and "Move Zeroes" is my first test.

I wrote down the process and the answer is correct, but when I submitted, it show as below:

Input: [2,1]

Output: [1,2]

Expected: [2,1]

Can anybody please tell me what is the problem? thanks very much!!!

```
void moveZeroes(vector<int>& nums) {
int mark=0;
if (nums.empty()) {
return;
}
for (int i=0; i<nums.size(); i++) {
if (nums[i]!=0 && i!=0) {
swap(nums[mark++],nums[i]);
}
}
}
```