Dutch_National_Flag_Algorithm.cpp

/*
This code is solution to sort colors problem on leetcode using Dutch Nationl Flag Algorithm
*/


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