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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. #define ll long long
  4. #define mod 1e9+7
  5. #define pb push_back
  6.  
  7.  
  8. bool check(string s, ll n)
  9. {
  10.  
  11.     // cout<<n<<"\n";
  12.     ll ptr1=0 , ptr2 = n-1;
  13.  
  14.     while(ptr1<=ptr2)
  15.     {
  16.         if(s[ptr1]!=s[ptr2])
  17.             return 0;
  18.  
  19.         ptr1++;
  20.         ptr2--;
  21.  
  22.     }
  23.  
  24.     return 1;
  25. }
  26.  
  27.  
  28. void solve()
  29. {
  30.     int a,b;
  31.     cin>>a>>b;
  32.  
  33.     string s;cin>>s;
  34.  
  35.     ll n = s.size();
  36.  
  37.     ll cnt0=0,cnt1=0;
  38.  
  39.     for(ll i=0;i<n;i++)
  40.     {
  41.         if(s[i]=='0')
  42.             cnt0++;
  43.         if(s[i]=='1')
  44.             cnt1++;
  45.     }
  46.  
  47.     int aa=a;
  48.     int bb=b;
  49.  
  50.     a-=cnt0;
  51.     b-=cnt1;
  52.  
  53.  
  54.  
  55.     ll ptr1=0,ptr2=n-1;
  56.  
  57.     while(ptr1<=ptr2)
  58.     {
  59.          // cout<<s<<"\n";
  60.          // cout<<ptr1<<" "<<ptr2<<"\n";
  61.  
  62.         if(s[ptr1]=='?' && s[ptr2]=='?')
  63.         {
  64.             if(a>b)
  65.             {
  66.                 s[ptr1]='0';
  67.                 s[ptr2]='0';
  68.                 ptr1==ptr2 ? a-=1 : a-=2;
  69.  
  70.                 ptr1++;
  71.                 ptr2--;
  72.                 continue;
  73.             }
  74.             if(b>a)
  75.             {
  76.                 s[ptr1]='1';
  77.                 s[ptr2]='1';
  78.                 ptr1==ptr2 ? b-=1 : b-=2;
  79.  
  80.                 ptr1++;
  81.                 ptr2--;
  82.  
  83.                 continue;
  84.             }
  85.  
  86.                 s[ptr1]='1';
  87.                 s[ptr2]='1';
  88.                 ptr1==ptr2 ? b-=1 : b-=2;
  89.  
  90.                 ptr1++;
  91.                 ptr2--;
  92.  
  93.                 continue;
  94.         }
  95.  
  96.         if(s[ptr1]=='?' && s[ptr2] == '1')
  97.         {
  98.             s[ptr1] = '1';
  99.             ptr1++;
  100.             ptr2--;
  101.             b-=1;
  102.             continue;
  103.         }
  104.  
  105.         if(s[ptr1]=='?' && s[ptr2] == '0')
  106.         {
  107.             s[ptr1] = '0';
  108.             ptr1++;
  109.             ptr2--;
  110.             a-=1;
  111.             continue;
  112.         }
  113.  
  114.         if(s[ptr1]=='1' && s[ptr2] == '?')
  115.         {
  116.             s[ptr2] = '1';
  117.             // cout<<s[ptr2];
  118.             ptr1++;
  119.             ptr2--;
  120.             b-=1;
  121.             continue;
  122.         }
  123.  
  124.         if(s[ptr1]=='0' && s[ptr2] == '?')
  125.         {
  126.             s[ptr2] = '0';
  127.             ptr1++;
  128.             ptr2--;
  129.             a-=1;
  130.             continue;
  131.         }
  132.  
  133.         ptr1++;
  134.         ptr2--;
  135.     }
  136.  
  137.     // cout<<a<<" "<<b<<"\n";
  138.  
  139.     if(a<0 || b<0){
  140.         cout<<"-1\n";
  141.         return ;
  142.     }
  143.  
  144.     ll  mn = aa+bb;
  145.  
  146.     if(check(s , mn))
  147.     {
  148.         cout<<s<<"\n";
  149.     }
  150.     else
  151.         cout<<"-1\n";
  152.  
  153.     // cout<<s;
  154. }
  155.  
  156. int  main()
  157. {
  158.     int t=1;
  159.     cin>>t;
  160.  
  161.     while(t--)
  162.     {
  163.         solve();
  164.     }
  165. }
Success #stdin #stdout 0.01s 5436KB
comments (?)
stdin 
Standard input is empty
stdout 
-1
https://ideone.com/dZeurz
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
public

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