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.

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.

C++(16ms):

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

C++(19ms):

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