Submission #18272984

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Source Code Expand

#define LOCAL
#define _USE_MATH_DEFINES
#include <array>
#include <cassert>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <vector>
#include <queue>
#include <stack>
#include <list>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <algorithm>
#include <complex>
#include <cmath>
#include <numeric>
#include <bitset>
#include <functional>
#include <random>
#include <ctime>

using namespace std;

template <typename A, typename B>
ostream& operator <<(ostream& out, const pair<A, B>& a) {
  out << "(" << a.first << "," << a.second << ")";
  return out;
}
template <typename T, size_t N>
ostream& operator <<(ostream& out, const array<T, N>& a) {
  out << "["; bool first = true;
  for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "]";
  return out;
}
template <typename T>
ostream& operator <<(ostream& out, const vector<T>& a) {
  out << "["; bool first = true;
  for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "]";
  return out;
}
template <typename T, class Cmp>
ostream& operator <<(ostream& out, const set<T, Cmp>& a) {
  out << "{"; bool first = true;
  for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "}";
  return out;
}
template <typename U, typename T, class Cmp>
ostream& operator <<(ostream& out, const map<U, T, Cmp>& a) {
  out << "{"; bool first = true;
  for (auto& p : a) { out << (first ? "" : ", "); out << p.first << ":" << p.second; first = 0;} out << "}";
  return out;
}
#ifdef LOCAL
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
#else
#define trace(...) 42
#endif
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
  cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << ": " << arg1 << " |";
  __f(comma + 1, args...);
}

typedef long long int64;
typedef pair<int, int> ii;
#define SZ(x) (int)((x).size())
const int INF = 1 << 29;
const int MOD = 1e9 + 7;
mt19937 mrand(random_device{}());
int rnd(int x) { return mrand() % x; }

struct fast_ios {
  fast_ios() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
  };
} fast_ios_;

int main() {
  int n;
  cin >> n;
  string c(4, ' ');
  for (int i = 0; i < 4; ++i) cin >> c[i];
  if (n <= 3) {
    cout << 1 << '\n';
    return 0;
  }

  set<string> dp, ndp;
  dp = {"AB"};
  vector<int> ret(n + 1, 1);
  for (int k = 3; k <= n && k <= 10; ++k) {
    ndp.clear();
    for (auto& s : dp) {
      for (int i = 0; i < k - 2; ++i) {
        int x = (s[i] - 'A') * 2 + (s[i + 1] - 'A');
        string t = s.substr(0, i + 1) + c[x] + s.substr(i + 1);
        ndp.insert(t);
      }
    }
    swap(dp, ndp);
    ret[k] = SZ(dp);
    // trace(k, SZ(dp));
  }
  if (n == 4) {
    cout << ret[n] << '\n';
    return 0;
  }

  if (ret[4] == ret[5]) {
    cout << 1 << '\n';
  } else if (ret[4] * 2 == ret[5]) {
    for (int i = 5; i <= n; ++i) {
      ret[i] = 2 * ret[i - 1] % MOD;
    }
    cout << ret[n] << '\n';
  } else {
    for (int i = 4; i <= n; ++i) {
      ret[i] = (ret[i - 1] + ret[i - 2]) % MOD;
    }
    cout << ret[n] << '\n';
  }
  return 0;
}

Submission Info

Compile Error

./Main.cpp:78:11: warning: unused variable 'INF' [-Wunused-const-variable]
const int INF = 1 << 29;
          ^
1 warning generated.

Judge Result