6_Question.cpp

// Airport security officials have confiscated several item of the passengers at the security check point.
// All the items have been dumped into a huge box (array). Each item possesses a certain amount of risk[0,1,2].
// Here, the risk severity of the items represent an array[] of N number of integer values.
// The task here is to sort the items based on their levels of risk in the array. The risk values range from 0 to 2.

// Example :

// Input :

// 7  -> Value of N

// [1,0,2,0,1,0,2]-> Element of arr[0] to arr[N-1], while input each element is separated by new line.

// Output :

// 0 0 0 1 1 2 2  -> Element after sorting based on risk severity 

// Example 2:

// input : 10  -> Value of N 

// [2,1,0,2,1,0,0,1,2,0] -> Element of arr[0] to arr[N-1], while input each element is separated by a new line.

// Output : 

// 0 0 0 0 1 1 1 2 2 2  ->Elements after sorting based on risk severity.

// Explanation:

// In the above example, the input is an array of size N consisting of only 0’s, 1’s and 2s.
// The output is a sorted array from 0 to 2 based on risk severity.

#include<bits/stdc++.h>
using namespace std;

int main(){
    int n;
    cin>>n;
    vector<int> arr(n);

    for(int i=0; i<n; i++){
        cin>>arr[i];
    }

    int l = 0, m = 0, h = n-1;
    while(m <= h){
        if(arr[m] == 0){
            swap(arr[l++],arr[m++]);
        }else if(arr[m] == 1){
            m++;
        }else{
            swap(arr[m],arr[h--]);
        }
    }

    for(int x : arr){
        cout<<x<<" ";
    }
    return 0;
}