Sort Colors

sort-colors.cpp

class Solution {
public:
    void sortColors(vector<int>& nums) {
        int p0 = 0;
        int p1 = 0;
        int p2 = nums.size() - 1;
        
        while (p1 <= p2) {
            if (nums[p1] == 1) {
                p1++;
            } else if (nums[p1] == 2) {
                swap(nums[p1], nums[p2]);
                p2--;
            } else {
                swap(nums[p0], nums[p1]);
                p0++;
                p1++;
            }
        }
    }
};