Problem p02671 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
typedef vector<vector<vector<bool>>> vvvb;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;
typedef vector<double> vd;
typedef vector<vd> vdd;

#define FOR(i, x, y) for (ll i = (ll)x; i < (ll)y; ++i)
#define REP(i, y) FOR(i, 0, y)
#define RFOR(i, x, y) for (ll i = (ll)x; i >= (ll)y; --i)
#define RREP(i, x) RFOR(i, x, 0)
#define ALL(a) a.begin(), a.end()
#define pb push_back
#define debug_print(x...)                                                      \\
  cerr << "line " << __LINE__ << " : ";                                        \\
  debug_print_in(x);

template <typename First> void debug_print_in(First first) {
  cerr << first << endl;
  return;
}

template <typename First, typename... Rest>
void debug_print_in(First first, Rest... rest) {
  cerr << first << " ";
  debug_print_in(rest...);
  return;
}

void IN(void) { return; }

template <typename First, typename... Rest>
void IN(First &first, Rest &...rest) {
  cin >> first;
  IN(rest...);
  return;
}

template <typename First> void OUT(First first) {
  cout << first << endl;
  return;
}

template <typename First, typename... Rest>
void OUT(First first, Rest... rest) {
  cout << first << " ";
  OUT(rest...);
  return;
}

template <class t, class u> void chmax(t &a, u b) {
  if (a < b)
    a = b;
};
template <class t, class u> void chmin(t &a, u b) {
  if (a > b)
    a = b;
};
int popcount(int t) { return __builtin_popcount(t); }  // GCC
int popcount(ll t) { return __builtin_popcountll(t); } // GCC

template <typename T> void vec_print(vector<T> VEC) {
  REP(i, VEC.size()) { cerr << VEC[i] << " "; }
  cerr << endl;
};

template <typename T>
void mat_print(vector<vector<T>> MAT){
    REP(i, MAT.size()){REP(j, MAT[i].size()){cerr << MAT[i][j] << " ";
}
cerr << endl;
}
}
;

constexpr int INF = (1 << 30);
constexpr ll INFLL = 1LL << 62;
constexpr long double EPS = 1e-12;
constexpr ll MOD = (ll)((1E+9) + 7);

ll N;
string T;

pair<vll, vll> solve(ll n) {
  if (n == 0) {
    vll P0 = {0};
    vll W0(T.size() + 1, 0);
    return make_pair(P0, W0);
  }
  auto PW_prev = solve(n - 1);
  auto P_old = PW_prev.first;
  auto W_old = PW_prev.second;

  /*
  for(auto ans : PW_prev.first){
    printf("%lld ", ans);
  }
  printf("\\n");

  for(auto tmp : PW_prev.second){
    printf("%lld ", tmp);
  }
  printf("\\n\\n");
  */

  vll P_new(P_old.size() * 3);
  vll D_new(P_old.size() * 3);
  vll W_new(W_old.size());

  vll S_ahead_count(P_old.size() * 3);
  ll S_count = 0;

  REP(i, D_new.size()) D_new[i] = i / P_old.size();

  REP(i, T.size()) {
    auto W = W_old[i];
    // debug_print(W);
    auto c = T[i];
    for (auto j = W; j < P_new.size(); j += P_old.size()) {
      if ((S_count - S_ahead_count[j]) % 2 == 1) {
        S_ahead_count[j] = S_count;
        D_new[j] = (3 - D_new[j]) % 3;
      }
      if (D_new[j] == 2)
        W_new[i] = j;
    }
    if (c == 'S') {
      S_count++;
    } else {
      for (auto j = W; j < P_new.size(); j += P_old.size()) {
        D_new[j] = (D_new[j] + 1) % 3;
      }
    }
  }

  // debug_print(i, W, c);
  REP(k, P_new.size()) {
    ll D_tmp = D_new[k];
    if ((S_count - S_ahead_count[k]) % 2 == 1) {
      D_tmp = (3 - D_new[k]) % 3;
    }
    P_new[k] = P_old[k % P_old.size()] + P_old.size() * D_tmp;
    // printf("%lld ", D_tmp);
  }

  /*
  printf("\\n");
  debug_print(i);
  */

  return make_pair(P_new, W_new);
}

int main() {
  cin.tie(0); // cut the cin and cout (default, std::flush is performed after
              // std::cin)
  ios::sync_with_stdio(
      false); // cut the iostream and stdio (DON'T endl; BUT "\\n";)

  IN(N);
  IN(T);

  auto PW = solve(N);

  for (auto ans : PW.first) {
    printf("%lld ", ans);
  }
  printf("\\n");

  /*
  for(auto tmp : PW.second){
    printf("%lld ", tmp);
  }
  printf("\\n");
  */

  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
typedef vector<vector<vector<bool>>> vvvb;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;
typedef vector<double> vd;
typedef vector<vd> vdd;

#define FOR(i, x, y) for (ll i = (ll)x; i < (ll)y; ++i)
#define REP(i, y) FOR(i, 0, y)
#define RFOR(i, x, y) for (ll i = (ll)x; i >= (ll)y; --i)
#define RREP(i, x) RFOR(i, x, 0)
#define ALL(a) a.begin(), a.end()
#define pb push_back
#define debug_print(x...)                                                      \\
  cerr << "line " << __LINE__ << " : ";                                        \\
  debug_print_in(x);

template <typename First> void debug_print_in(First first) {
  cerr << first << endl;
  return;
}

template <typename First, typename... Rest>
void debug_print_in(First first, Rest... rest) {
  cerr << first << " ";
  debug_print_in(rest...);
  return;
}

void IN(void) { return; }

template <typename First, typename... Rest>
void IN(First &first, Rest &...rest) {
  cin >> first;
  IN(rest...);
  return;
}

template <typename First> void OUT(First first) {
  cout << first << endl;
  return;
}

template <typename First, typename... Rest>
void OUT(First first, Rest... rest) {
  cout << first << " ";
  OUT(rest...);
  return;
}

template <class t, class u> void chmax(t &a, u b) {
  if (a < b)
    a = b;
};
template <class t, class u> void chmin(t &a, u b) {
  if (a > b)
    a = b;
};
int popcount(int t) { return __builtin_popcount(t); }  // GCC
int popcount(ll t) { return __builtin_popcountll(t); } // GCC

template <typename T> void vec_print(vector<T> VEC) {
  REP(i, VEC.size()) { cerr << VEC[i] << " "; }
  cerr << endl;
};

template <typename T>
void mat_print(vector<vector<T>> MAT){
    REP(i, MAT.size()){REP(j, MAT[i].size()){cerr << MAT[i][j] << " ";
}
cerr << endl;
}
}
;

constexpr int INF = (1 << 30);
constexpr ll INFLL = 1LL << 62;
constexpr long double EPS = 1e-12;
constexpr ll MOD = (ll)((1E+9) + 7);

ll N;
string T;

pair<vll, vll> solve(ll n) {
  if (n == 0) {
    vll P0 = {0};
    vll W0(T.size() + 1, 0);
    return make_pair(P0, W0);
  }
  auto PW_prev = solve(n - 1);
  auto P_old = PW_prev.first;
  auto W_old = PW_prev.second;

  /*
  for(auto ans : PW_prev.first){
    printf("%lld ", ans);
  }
  printf("\\n");

  for(auto tmp : PW_prev.second){
    printf("%lld ", tmp);
  }
  printf("\\n\\n");
  */

  vll P_new(P_old.size() * 3);
  vll D_new(P_old.size() * 3);
  vll W_new(W_old.size());

  vll S_ahead_count(P_old.size() * 3);
  ll S_count = 0;

  REP(i, D_new.size()) D_new[i] = i / P_old.size();

  REP(i, T.size()) {
    auto W = W_old[i];
    // debug_print(W);
    auto c = T[i];
    for (auto j = W; j < P_new.size(); j += P_old.size()) {
      if ((S_count - S_ahead_count[j]) % 2 == 1) {
        S_ahead_count[j] = S_count;
        D_new[j] = (3 - D_new[j]) % 3;
      }
      if (D_new[j] == 2)
        W_new[i] = j;
    }
    if (c == 'S') {
      S_count++;
    } else {
      for (auto j = W; j < P_new.size(); j += P_old.size()) {
        D_new[j] = (D_new[j] + 1) % 3;
      }
    }

    // debug_print(i, W, c);
    REP(k, P_new.size()) {
      ll D_tmp = D_new[k];
      if ((S_count - S_ahead_count[k]) % 2 == 1) {
        D_tmp = (3 - D_new[k]) % 3;
      }
      P_new[k] = P_old[k % P_old.size()] + P_old.size() * D_tmp;
      // printf("%lld ", D_tmp);
    }

    /*
    printf("\\n");
    debug_print(i);
    */
  }

  return make_pair(P_new, W_new);
}

int main() {
  cin.tie(0); // cut the cin and cout (default, std::flush is performed after
              // std::cin)
  ios::sync_with_stdio(
      false); // cut the iostream and stdio (DON'T endl; BUT "\\n";)

  IN(N);
  IN(T);

  auto PW = solve(N);

  for (auto ans : PW.first) {
    printf("%lld ", ans);
  }
  printf("\\n");

  /*
  for(auto tmp : PW.second){
    printf("%lld ", tmp);
  }
  printf("\\n");
  */

  return 0;
}