Codeforces Round #303 Equidistant String

Little Susie loves strings. Today she calculates distances between them. As Susie is a small girl after all, her strings contain only digits zero and one. She uses the definition of Hamming distance:

We will define the distance between two strings s andt of the same length consisting of digits zero and one as the number of positionsi, such that s_i isn't equal tot_i.

As besides everything else Susie loves symmetry, she wants to find for two stringss and t of lengthn such string p of lengthn, that the distance from p to s was equal to the distance fromp to t.

It's time for Susie to go to bed, help her find such string p or state that it is impossible.

Input

The first line contains string s of lengthn.

The second line contains string t of lengthn.

The length of string n is within range from1 to 10⁵. It is guaranteed that both strings contain only digits zero and one.

Output

Print a string of length n, consisting of digits zero and one, that meets the problem statement. If no such string exist, print on a single line "impossible" (without the quotes).

If there are multiple possible answers, print any of them.

Sample test(s)

Input

0001
1011

Output

Input

000
111

Output

impossible

#include <iostream>
#include <cstring>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#define LL long long
#define INF 0x3f3f3f3f

using namespace std;

char s[100010],a[1000010],p[100010];
int main()
{
    while(cin>>s>>a)
    {
        int len = strlen(s);
        int ant = 0;
        for(int i=0;i<len;i++)
        {
            if(s[i] == a[i])
                p[i] = a[i];
            else
            {
                ant++;
                if(ant%2)
                    p[i] = s[i];
                else
                    p[i] = a[i];
            }
        }
        if(ant % 2)
            cout<<"impossible"<<endl;
        else
            cout<<p<<endl;
    }
    return 0;
}

来源：CSDN

作者：__铭

链接：https://blog.csdn.net/Code_KK/article/details/47379477

标签

string

impossible