Equidistant String.cpp

/*
RAJAT SINGH
VIT VELLORE
*/
 
#include<bits/stdc++.h>
using namespace std;
#define ll   long long 
//#define max 706000
#define gc getchar_unlocked
#define pc putchar_unlocked
//inline void get(int *p){register  int n=0,sign=1,a=gc();while(a<'0'||a>'9'){ if(a=='-'){sign=-1;a=gc();break;} a=gc();}while(a>='0' && a<='9'){n=(n<<1)+(n<<3)+a-'0';a=gc();}*p=n*sign;}
  
 
//inline void put(int n){char d[10];int i=0;if(n<0){pc('-');n=-n;}do{d[i++]=n%10+'0';n=n/10;}while(n);while(i)pc(d[--i]);pc('\n');}
#define     sc(a)  scanf("%lld",&a) 
#define     p(a)  printf("%lld\n",a) 
#define     l(i,a)  for(i=0;i<a;i++)
#define     re(j,a,b)  for(j=a;j<=b;j++)  
# define ll   long long 
#define modu 1000000007
int modular_pow(ll int  base, ll int  exponent,int m)
{
    if(exponent==0)
    return 1;
    else if(exponent%2==0){
        ll int res=modular_pow(base,exponent/2,m);
        return (res*res +m)%m;
        
        
    }
    else{
        return (modular_pow(base,exponent-1,m) * base)%m;
        
    }
}
 
 
 
 int gcd(int a,int b){
    if(b==0)
    return a;//gcd
    else return gcd(b,a%b);
 }
 
bool chek(int x){
    return (x&&!(x&(x-1)));// power of 2
}
int onebits(int n){
    return __builtin_popcount(n);//count number od set bits in a number
 
}
 
 
/*
finaaly it worked!!!!!!
 
*/
vector< pair< ll , ll > >vv;
vector< ll >r1;
vector< ll >r2;
bool che(ll r1, ll r2){
	for(int u=0;u<vv.size();u++){
		if(vv[u].first>r1 && vv[u].second>r2) return false;
		
	}
	return true;
	
}

 int main(){
//freopen("input.txt","r",stdin);
string s,k;

cin>>s>>k;
int c=0;
	vector< int >v(s.length()+1,0);
	for(int u=0;u<s.length();u++){
		if(s[u]==k[u]){
	    if(s[u]=='0')
		v[u]=0;
		else v[u]=1;	
		c++;
		
	}}
	int se=s.length()-c;
	if(se%2==1)puts("impossible");
	else{
		int cc=0;
		for(int u=0;u<s.length();u++){
			if(s[u]!=k[u]){
				if(cc%2==0){
					if(s[u]-'0'==0)
					v[u]=1;
					else v[u]=0;
					
				}
				else{
					if(k[u]-'0'==0)
					v[u]=1;
					else v[u]=0;
				}
				cc++;
				
				//se--;
			}
			if(se==0)break;
		}
		for(int u=0;u<s.length();u++)cout<<v[u];
		cout<<endl;
		
	}
	



return 0;}