SOLUTION TO CODEOJ PROBLEM : ITS BIT GAME (AASF PC)

http://www.codeoj.com/problemshow.jsp?q=PRACTICEP28&c=PRACTICE

#include <bits/stdc++.h>
#define MAX 1001
using namespace std;

int main() {
    int t;
    cin>>t;
    while(t--)
    {

        int arr[MAX]={0};
 
        long long int n,x;
        cin>>n>>x;
        int i=0;
        while(n!=0)
        {
            arr[i]=n%2;
            n=n/2;
            i++;
        }
        int arr2[MAX];
        fill(arr2,arr2+1000,2);      //marked non flips with 2
        int len1=i;
        for(int j=0;j<len1;j++)
          {
            if(arr[j]==1)
                 arr2[j]=0;
          }
        int arr1[MAX]={0};
        i=0;
        while(x!=0)
        {
            arr1[i]=x%2;
            x=x/2;
            i++;
        }
        int len2=i;
        i=0;
        int y=0;
        while(y<len2)
        {
            if(arr2[i]==2)
               {  arr2[i]=arr1[y];   y++;  i++;  }
              else
                 i++;
        }
        for(int u=i;u<1000;u++)
        {
            if(arr2[u]==2)
                arr2[u]=0;
        }
        long long int res=0;
        for(int f=0;f<1000;f++)
        {
            res=res+(arr2[f]*pow(2,f));
        }
        cout<<res<<endl;
                
    }
    // your code goes here
    return 0;
}