Sort Color

please think about about the while exit condition!!

class Solution{
public:
    /**
     * @param nums: A list of integer which is 0, 1 or 2 
     * @return: nothing
     */    
    void sortColors(vector<int> &nums) {
        // write your code here
        if(nums.size() == 0)
        {
            return ;
        }

        int l = 0;
        int i = 0;
        int r = nums.size()-1;

        while(i <= r)
        {
            if(nums[i] == 0)
            {
                swap(nums, l++, i++);
            }
            else if(nums[i] == 1)
            {
                i++;
            }
            else
            {
                swap(nums, i, r--);
            }
        }
    }

    void swap(vector<int>& nums, int left, int right)
    {
        int t = nums[left];
        nums[left] = nums[right];
        nums[right] = t;
    }
};

code 2

class Solution {
public:
    void sortColors(vector<int>& nums) {
        int n = nums.size();
        if(n == 0)
        {
            return ;
        }

        int i = 0;
        int j = 0;
        int k = n-1;

        while(j <= k)
        {
            if(nums[j] == 0)
            {
                swap(nums, i, j);
                i++;
                j++;
            }
            else if(nums[j] == 1)
            {
                j++;
            }
            else
            {
                swap(nums, j, k);
                k--;
            }
        }
    }

    void swap(vector<int>& nums, int i, int j)
    {
        int tmp = nums[i];
        nums[i] = nums[j];
        nums[j] = tmp;
    }
};