Codeforces Round #545 (Div. 2) D

#include<bits/stdc++.h>
using namespace std;
#define mid int m = (l + r) >> 1
#define ll long long
const int M = 1e5 + 10;
string s,s1;
int main()
{
    int a=0,b=0,a1=0,b1=0;
    cin>>s;
    int len = s.size();
    cin>>s1;
    int len1 = s1.size();
    for(int i = 0;i < len;i ++){
        if(s[i]==‘0‘) a++;
        else b++;
    }
    for(int i = 0;i < len1;i ++){
        if(s1[i]==‘0‘) a1++;
        else b1++;
    }
    int k;
    if(a1==0) k = b/b1;
    else if(b1 == 0) k = a/a1;
    else k = min(a/a1,b/b1);
    if(k==0){
        cout<<s<<endl;
    }
    else{
        int en = len1;
        int aa = 0,bb = 0,aa1 = 0,bb1 =0;
        for(int i = 1;i < len1;i ++){
            int flag = 0;
            if(s1[i-1]==‘0‘) aa++;
            else bb++;
            if(s1[len1-i]==‘0‘) aa1++;
            else bb1++;
            if(aa!=aa1||bb!=bb1) continue;
            for(int j = 0;j < len1-i;j ++){
                if(s1[i+j]!=s1[j]){
                    flag = 1;
                    break;
                }
            }
            if(flag == 0){
                en = i;
                break;
            }
        }
        //cout<<en<<endl;
        int a2 = 0;int b2 = 0;
        if(en != len1){
            for(int i = len1 - en;i < len1;i ++){
                if(s1[i]==‘0‘) a2++;
                else b2++;
            }
        }
        else {
            a2 = a1,b2 = b1;
        }
        a-=a1; b-=b1;
        cout<<s1;
        int k1;
        if(a2==0) k1 = b/b2;
        else if(b2 == 0) k1 = a/a2;
        else k1 = min(a/a2,b/b2);
        for(int i = 1;i <= k1;i ++){
            for(int j = len1-en;j < len1;j ++)
                cout<<s1[j];
        }
        a -= a2*k1; b -= b2*k1;
        for(int i = 1;i <= a;i ++)
            cout<<0;
        for(int i = 1;i <= b;i ++)
            cout<<1;
        cout<<endl;
    }
}