sort012.cpp

#include <iostream>
using namespace std;
/**
	We could have done this problem by coounting the occurence of elements
*/
int main() {
	int testCases;
	cin>>testCases;
	for(int i = 0 ; i < testCases; i++) {
	    int n;
	    cin>>n;
	    int arr[n];
	    for(int j =0 ; j < n ; j++) {
	        cin>>arr[j];
	    }
	    int pointer = 0, temp;
	    for(int j =0 ; j < n ; j++) {
	        if(arr[j]==0) {
	            temp = arr[j];
	            arr[j]=arr[pointer];
	            arr[pointer]= temp;
	            pointer++;
	        }
	    }
	    for(int j =0 ; j < n ; j++) {
	        if(arr[j]==1) {
	            temp = arr[j];
	            arr[j]=arr[pointer];
	            arr[pointer]= temp;
	            pointer++;
	       }
	    }
	    for(int j =0 ; j < n ; j++) {
	        cout<<arr[j]<<" ";
	    }
	    cout<<endl;
	}
	return 0;
}