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.

把所有非0元素全部前移，最後省下的位置補0。j下標只有賦值以後才能++, i下表負責找非0元素，找到了給j下標然後繼續找

 1 class Solution {
 2 public:
 3     void moveZeroes(vector<int>& nums) {
 4         int j = 0;
 5         // move all the nonzero elements advance
 6         for (int i = 0; i < nums.size(); i++) {
 
 7             if (nums[i] != 0) {
 8                 nums[j++] = nums[i];
 9             }
10         }
11         for (;j < nums.size(); j++) {
12             nums[j] = 0;
13         }
14     }
15 };

283. Move Zeroes