Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <ctype.h>
#include <deque>
#include <queue>
#include <cstring>
#include <set>
#include <list>
#include <map>
#include <random>
#include <unordered_map>
#include <stdio.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef std::vector<int> vi;
typedef std::vector<bool> vb;
typedef std::vector<string> vs;
typedef std::vector<double> vd;
typedef std::vector<long long> vll;
typedef std::vector<std::vector<int> > vvi;
typedef vector<vll> vvll;
typedef std::vector<std::pair<int, int> > vpi;
typedef vector<vpi> vvpi;
typedef std::pair<int, int> pi;
typedef std::pair<ll, ll> pll;
typedef std::vector<pll> vpll;

const long long mod = 1000000007;

#define all(c) (c).begin(),(c).end()
#define forn(i, a, b) for(int i = a; i < b; i++)

#define pb push_back
#define mp make_pair
bitset<2000> ar[2001];
bitset<2000> br[2001];
bitset<2000> brc[2001];
bitset<2000> blc[2001];
int main()
{
    string as,bs;
    cin>>as>>bs;
    int n = as.size();
    bitset<2000> a,b;
    forn(i,0,n) if(as[i] == '1') a.set(i);
    forn(i,0,n) if(bs[i] == '1') b.set(i);
    if(b.count() == 0) {
        if(a.count() == 0) cout<<0;
        else cout<<-1;
        return 0;
    }
    int best = n;
    forn(i,0,n+1) {
        ar[i] = a;
        br[i] = b;
        int bit = a[0];
        a>>=1;
        a[n-1] = bit;
        bit = b[0];
        b>>=1;
        b[n-1] = bit;
    }
    int ans = 1e9;
    b = br[0];
    a = ar[0];
    brc[0] = br[0];
    forn(i,1,n+1) brc[i] = brc[i-1] | br[n-i];
    blc[0] = br[0];
    forn(i,1,n+1) blc[i] = blc[i-1] | br[i];
    forn(mr,0,n+1) {
        bitset<2000> diff = a ^ br[n-mr];
        int cand = diff.count();
        int l = -1;
        int r = n;
        while(r-l>1) {
            int m = (r+l+1)/2;
            bitset<2000> btest = (blc[m] | brc[mr]).flip();
            if((btest & diff).count() == 0) {
                r = m;
                ans = min(ans, cand + mr+2*m);
            }
            else l = m;
        }
    }
    forn(ml,0,n+1) {
        bitset<2000> diff = a ^ br[ml];
        int cand = diff.count();
        int l = -1;
        int r = n;
        while(r-l>1) {
            int m = (r+l+1)/2;
            bitset<2000> btest = (brc[m] | blc[ml]).flip();
            if((btest & diff).count() == 0) {
                r = m;
                ans = min(ans, cand + ml+2*m);
            }
            else l = m;
        }
    }
    cout<<ans;
}



Compiler output:
a.cc:40:1: error: 'bitset' does not name a type
   40 | bitset<2000> ar[2001];
      | ^~~~~~
a.cc:41:1: error: 'bitset' does not name a type
   41 | bitset<2000> br[2001];
      | ^~~~~~
a.cc:42:1: error: 'bitset' does not name a type
   42 | bitset<2000> brc[2001];
      | ^~~~~~
a.cc:43:1: error: 'bitset' does not name a type
   43 | bitset<2000> blc[2001];
      | ^~~~~~
a.cc: In function 'int main()':
a.cc:49:5: error: 'bitset' was not declared in this scope
   49 |     bitset<2000> a,b;
      |     ^~~~~~
a.cc:14:1: note: 'std::bitset' is defined in header '<bitset>'; this is probably fixable by adding '#include <bitset>'
   13 | #include <unordered_map>
  +++ |+#include <bitset>
   14 | #include <stdio.h>
a.cc:49:18: error: 'a' was not declared in this scope
   49 |     bitset<2000> a,b;
      |                  ^
a.cc:49:20: error: 'b' was not declared in this scope
   49 |     bitset<2000> a,b;
      |                    ^
a.cc:59:9: error: 'ar' was not declared in this scope; did you mean 'as'?
   59 |         ar[i] = a;
      |         ^~
      |         as
a.cc:60:9: error: 'br' was not declared in this scope; did you mean 'bs'?
   60 |         br[i] = b;
      |         ^~
      |         bs
a.cc:69:9: error: 'br' was not declared in this scope; did you mean 'bs'?
   69 |     b = br[0];
      |         ^~
      |         bs
a.cc:70:9: error: 'ar' was not declared in this scope; did you mean 'as'?
   70 |     a = ar[0];
      |         ^~
      |         as
a.cc:71:5: error: 'brc' was not declared in this scope
   71 |     brc[0] = br[0];
      |     ^~~
a.cc:73:5: error: 'blc' was not declared in this scope
   73 |     blc[0] = br[0];
      |     ^~~
a.cc:76:22: error: 'diff' was not declared in this scope
   76 |         bitset<2000> diff = a ^ br[n-mr];
      |                      ^~~~
a.cc:82:26: error: 'btest' was not declared in this scope; did you mean 'best'?
   82 |             bitset<2000> btest = (blc[m] | brc[mr]).flip();
      |                          ^~~~~
      |                          best
a.cc:91:22: error: 'diff' was not declared in this scope
   91 |         bitset<2000> diff = a ^ br[ml];
      |                      ^~~~
a.cc:97:26: error: 'btest' was not declared in this scope; did you mean 'best'?
   97 |             bitset<2000> btest = (brc[m] | blc[ml]).flip();
      |                          ^~~~~
      |                          best