Language: C++

#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <set>
#include <vector>
#include <map>
#include <cmath>
#include <algorithm>
#include <memory.h>
#include <string>
#include <sstream>
#include <cstdlib>
#include <ctime>
#include <cassert>

using namespace std;

typedef long long LL;
typedef pair<int,int> PII;

#define MP make_pair
#define PB push_back
#define FF first
#define SS second

#define FORN(i, n) for (int i = 0; i <  (int)(n); i++)
#define FOR1(i, n) for (int i = 1; i <= (int)(n); i++)
#define FORD(i, n) for (int i = (int)(n) - 1; i >= 0; i--)

#define DEBUG(X) { cout << #X << " = " << (X) << endl; }
#define PR0(A,n) { cout << #A << " = "; FORN(_,n) cout << A[_] << ' '; cout << endl; }

#define MOD 1000000007
#define INF 2000000000

int GLL(LL& x) {
    return scanf("%lld", &x);
}

int GI(int& x) {
    return scanf("%d", &x);
}

int n;

string a, b;

const int MAXL = 2005;

vector<bitset<MAXL>> v;

int main() {
    cin >> a >> b;

    n = a.size();

    FORN(i, n) {
        v.PB(bitset<MAXL>());

        FORN(j, n) {
            if (b[(i+j)%n] == '1') {
                v[i].set(j);
            }
        }
    }

    int res = INF;

    bitset<MAXL> canflip;

    // Shift left.

    FORN(i, n) {  // A[i] goes to A[0]
        bitset<MAXL> needflip;
        needflip.reset();

        int pc = 0;

        FORN(j, n) {
            if (b[j] != a[(i+j) % n]) {
                needflip.set((i+j) % n);
                pc++;
            }
        }

        canflip |= v[(n-i) % n];

        auto t_canflip = canflip;

        FORN(j, n) {
            if ((needflip & t_canflip) == needflip) {
                res = min(res, pc + i + 2 * j);
            }
            else {
                t_canflip |= v[(j+1)%n];
            }
        }
    }

    canflip.reset();

    for (int i = n; i >= 1; i--) {  // A[i] goes to A[0]
        bitset<MAXL> needflip;
        needflip.reset();

        int pc = 0;

        FORN(j, n) {
            if (b[j] != a[(i+j) % n]) {
                needflip.set((i+j) % n);
                pc++;
            }
        }

        canflip |= v[(n-i) % n];

        auto t_canflip = canflip;

        FORN(j, n) {
            if ((needflip & t_canflip) == needflip) {
                res = min(res, pc + (n-i) + 2 * j);
            }
            else {
                t_canflip |= v[(j+1)%n];
            }
        }
    }


    if (res < INF) {
        cout << res << "\n";
    }
    else {
        cout << -1 << "\n";
    }

    return 0;
}


Compiler output:
a.cc:50:8: error: 'bitset' was not declared in this scope
   50 | vector<bitset<MAXL>> v;
      |        ^~~~~~
a.cc:15:1: note: 'std::bitset' is defined in header '<bitset>'; this is probably fixable by adding '#include <bitset>'
   14 | #include <cassert>
  +++ |+#include <bitset>
   15 | 
a.cc:50:15: error: template argument 1 is invalid
   50 | vector<bitset<MAXL>> v;
      |               ^~~~
a.cc:50:15: error: template argument 2 is invalid
a.cc:50:19: error: expected unqualified-id before '>' token
   50 | vector<bitset<MAXL>> v;
      |                   ^~
a.cc: In function 'int main()':
a.cc:58:9: error: 'v' was not declared in this scope
   58 |         v.PB(bitset<MAXL>());
      |         ^
a.cc:58:14: error: 'bitset' was not declared in this scope
   58 |         v.PB(bitset<MAXL>());
      |              ^~~~~~
a.cc:58:14: note: 'std::bitset' is defined in header '<bitset>'; this is probably fixable by adding '#include <bitset>'
a.cc:58:27: error: expected primary-expression before ')' token
   58 |         v.PB(bitset<MAXL>());
      |                           ^
a.cc:69:5: error: 'bitset' was not declared in this scope
   69 |     bitset<MAXL> canflip;
      |     ^~~~~~
a.cc:69:5: note: 'std::bitset' is defined in header '<bitset>'; this is probably fixable by adding '#include <bitset>'
a.cc:69:18: error: 'canflip' was not declared in this scope
   69 |     bitset<MAXL> canflip;
      |                  ^~~~~~~
a.cc:74:22: error: 'needflip' was not declared in this scope
   74 |         bitset<MAXL> needflip;
      |                      ^~~~~~~~
a.cc:86:20: error: 'v' was not declared in this scope
   86 |         canflip |= v[(n-i) % n];
      |                    ^
a.cc:103:22: error: 'needflip' was not declared in this scope
  103 |         bitset<MAXL> needflip;
      |                      ^~~~~~~~
a.cc:115:20: error: 'v' was not declared in this scope
  115 |         canflip |= v[(n-i) % n];
      |                    ^