Problem p02589 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#include <cassert>
typedef long long int ll;
using namespace std;

// @@ !! LIM(debug rollingHash)
// --> f:<< debug rollingHash
// ---- inserted function << from util.cc
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << "(" << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << "(" << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << ", "
     << get<3>(t) << ")";
  return os;
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << '[';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << ']';

  return os;
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T>
ostream &operator<<(ostream &os, const unordered_set<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T> ostream &operator<<(ostream &os, const multiset<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin())
      os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin())
      os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T, typename T2>
ostream &operator<<(ostream &os, const queue<T, T2> &orig) {
  queue<T, T2> que(orig);
  bool first = true;
  os << '[';
  while (!que.empty()) {
    T x = que.front();
    que.pop();
    if (!first)
      os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T, typename T2, typename T3>
ostream &operator<<(ostream &os, const priority_queue<T, T2, T3> &orig) {
  priority_queue<T, T2, T3> pq(orig);
  bool first = true;
  os << '[';
  while (!pq.empty()) {
    T x = pq.top();
    pq.pop();
    if (!first)
      os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T> ostream &operator<<(ostream &os, const stack<T> &st) {
  stack<T> tmp(st);
  os << '[';
  bool first = true;
  while (!tmp.empty()) {
    T &t = tmp.top();
    if (first)
      first = false;
    else
      os << ", ";
    os << t;
    tmp.pop();
  }
  os << ']';
  return os;
}

#if __cplusplus >= 201703L
template <typename T> ostream &operator<<(ostream &os, const optional<T> &t) {
  if (t.has_value())
    os << "v(" << t.value() << ")";
  else
    os << "nullopt";
  return os;
}
#endif

// ---- end <<
// ---- inserted library file debug.cc
template <class... Args> string dbgFormat(const char *fmt, Args... args) {
  size_t len = snprintf(nullptr, 0, fmt, args...);
  char buf[len + 1];
  snprintf(buf, len + 1, fmt, args...);
  return string(buf);
}

template <class Head> void dbgLog(Head &&head) { cerr << head << endl; }

template <class Head, class... Tail> void dbgLog(Head &&head, Tail &&...tail) {
  cerr << head << " ";
  dbgLog(forward<Tail>(tail)...);
}

#if DEBUG
#define DLOG(...) dbgLog(__VA_ARGS__)
#define DFMT(...) cerr << dbgFormat(__VA_ARGS__) << endl
#define DCALL(func, ...) func(__VA_ARGS__)
#else
#define DLOG(...)
#define DFMT(...)
#define DCALL(func, ...)
#endif

#if DEBUG_LIB
#define DLOG_LIB(...) dbgLog(__VA_ARGS__)
#define DFMT_LIB(...) cerr << dbgFormat(__VA_ARGS__) << endl
#define DCALL_LIB(func, ...) func(__VA_ARGS__)
#else
#define DLOG_LIB(...)
#define DFMT_LIB(...)
#define DCALL_LIB(func, ...)
#endif

// ---- end debug.cc
// ---- inserted library file rollingHash.cc

// By keymoon
//     https://qiita.com/keymoon/items/11fac5627672a6d6a9f6
struct RollingHash {
  static random_device rand_dev;
  static mt19937 rng;

  using u64 = unsigned long long;
  static constexpr u64 mod = (1ULL << 61) - 1;
  static constexpr u64 mask30 = (1ULL << 30) - 1;
  static constexpr u64 mask31 = (1ULL << 31) - 1;
  static constexpr u64 mask61 = (1ULL << 61) - 1;
  static constexpr u64 positivizer = mod * 4;

  static u64 mul(u64 a, u64 b) {
    u64 au = a >> 31;
    u64 ad = a & mask31;
    u64 bu = b >> 31;
    u64 bd = b & mask31;
    u64 c = ad * bu + au * bd;
    u64 cu = c >> 30;
    u64 cd = c & mask30;
    return au * bu * 2 + cu + (cd << 31) + ad * bd;
  }

  static u64 calc_mod(u64 x) {
    u64 xu = x >> 61;
    u64 xd = x & mask61;
    u64 res = xu + xd;
    if (res >= mod)
      res -= mod;
    return res;
  }

  vector<vector<u64>> hash;
  vector<u64> pow_memo;
  u64 base;

  RollingHash() : hash(), pow_memo({1}) {
    uniform_int_distribution<> dist(1000, 1ULL << 20);
    base = dist(rng);
  }

  int reg(string s) {
    int n = s.size();
    vector<u64> hs(n + 1);
    for (int i = 0; i < n; i++) {
      hs[i + 1] = calc_mod(mul(hs[i], base) + s[i]);
    }
    hash.push_back(move(hs));
    while ((int)pow_memo.size() < n + 1) {
      pow_memo.push_back(calc_mod(mul(pow_memo[pow_memo.size() - 1], base)));
    }
    return hash.size() - 1;
  }

  u64 get_hash(int idx, int start, int len) {
    return calc_mod(hash[idx][start + len] + positivizer -
                    mul(hash[idx][start], pow_memo[len]));
  }
};
random_device RollingHash::rand_dev;
mt19937 RollingHash::rng(RollingHash::rand_dev());

// ---- end rollingHash.cc
// @@ !! LIM  -- end mark --

int main(/* int argc, char *argv[] */) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << setprecision(20);

  using u64 = unsigned long long;

  RollingHash rh;

  ll N;
  cin >> N;
  vector<u64> init1(N);
  vector<char> last1(N);
  unordered_map<u64, vector<ll>> mp;
  for (ll i = 0; i < N; i++) {
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    ll idx = rh.reg(s);
    ll sz = s.size();
    init1[i] = rh.get_hash(idx, 0, sz - 1);
    last1[i] = s[sz - 1] - 'a';
    vector<ll> app(26);
    for (ll j = sz - 1; j >= 0; j--) {
      app[s[j] - 'a'] = 1;
      u64 hash = rh.get_hash(idx, 0, j);
      auto it = mp.find(hash);
      if (it == mp.end()) {
        mp[hash] = app;
      } else {
        for (ll t = 0; t < 26; t++) {
          if (app[t])
            it->second[t]++;
        }
      }
    }
  }
  ll ans = 0;
  for (ll i = 0; i < N; i++) {
    ans += mp[init1[i]][last1[i]] - 1;
  }

  cout << ans << endl;
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <cassert>
typedef long long int ll;
using namespace std;

// @@ !! LIM(debug rollingHash)
// --> f:<< debug rollingHash
// ---- inserted function << from util.cc
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << "(" << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << "(" << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << ", "
     << get<3>(t) << ")";
  return os;
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << '[';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << ']';

  return os;
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T>
ostream &operator<<(ostream &os, const unordered_set<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T> ostream &operator<<(ostream &os, const multiset<T> &v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin())
      os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin())
      os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T, typename T2>
ostream &operator<<(ostream &os, const queue<T, T2> &orig) {
  queue<T, T2> que(orig);
  bool first = true;
  os << '[';
  while (!que.empty()) {
    T x = que.front();
    que.pop();
    if (!first)
      os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T, typename T2, typename T3>
ostream &operator<<(ostream &os, const priority_queue<T, T2, T3> &orig) {
  priority_queue<T, T2, T3> pq(orig);
  bool first = true;
  os << '[';
  while (!pq.empty()) {
    T x = pq.top();
    pq.pop();
    if (!first)
      os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T> ostream &operator<<(ostream &os, const stack<T> &st) {
  stack<T> tmp(st);
  os << '[';
  bool first = true;
  while (!tmp.empty()) {
    T &t = tmp.top();
    if (first)
      first = false;
    else
      os << ", ";
    os << t;
    tmp.pop();
  }
  os << ']';
  return os;
}

#if __cplusplus >= 201703L
template <typename T> ostream &operator<<(ostream &os, const optional<T> &t) {
  if (t.has_value())
    os << "v(" << t.value() << ")";
  else
    os << "nullopt";
  return os;
}
#endif

// ---- end <<
// ---- inserted library file debug.cc
template <class... Args> string dbgFormat(const char *fmt, Args... args) {
  size_t len = snprintf(nullptr, 0, fmt, args...);
  char buf[len + 1];
  snprintf(buf, len + 1, fmt, args...);
  return string(buf);
}

template <class Head> void dbgLog(Head &&head) { cerr << head << endl; }

template <class Head, class... Tail> void dbgLog(Head &&head, Tail &&...tail) {
  cerr << head << " ";
  dbgLog(forward<Tail>(tail)...);
}

#if DEBUG
#define DLOG(...) dbgLog(__VA_ARGS__)
#define DFMT(...) cerr << dbgFormat(__VA_ARGS__) << endl
#define DCALL(func, ...) func(__VA_ARGS__)
#else
#define DLOG(...)
#define DFMT(...)
#define DCALL(func, ...)
#endif

#if DEBUG_LIB
#define DLOG_LIB(...) dbgLog(__VA_ARGS__)
#define DFMT_LIB(...) cerr << dbgFormat(__VA_ARGS__) << endl
#define DCALL_LIB(func, ...) func(__VA_ARGS__)
#else
#define DLOG_LIB(...)
#define DFMT_LIB(...)
#define DCALL_LIB(func, ...)
#endif

// ---- end debug.cc
// ---- inserted library file rollingHash.cc

// By keymoon
//     https://qiita.com/keymoon/items/11fac5627672a6d6a9f6
struct RollingHash {
  static random_device rand_dev;
  static mt19937 rng;

  using u64 = unsigned long long;
  static constexpr u64 mod = (1ULL << 61) - 1;
  static constexpr u64 mask30 = (1ULL << 30) - 1;
  static constexpr u64 mask31 = (1ULL << 31) - 1;
  static constexpr u64 mask61 = (1ULL << 61) - 1;
  static constexpr u64 positivizer = mod * 4;

  static u64 mul(u64 a, u64 b) {
    u64 au = a >> 31;
    u64 ad = a & mask31;
    u64 bu = b >> 31;
    u64 bd = b & mask31;
    u64 c = ad * bu + au * bd;
    u64 cu = c >> 30;
    u64 cd = c & mask30;
    return au * bu * 2 + cu + (cd << 31) + ad * bd;
  }

  static u64 calc_mod(u64 x) {
    u64 xu = x >> 61;
    u64 xd = x & mask61;
    u64 res = xu + xd;
    if (res >= mod)
      res -= mod;
    return res;
  }

  vector<vector<u64>> hash;
  vector<u64> pow_memo;
  u64 base;

  RollingHash() : hash(), pow_memo({1}) {
    uniform_int_distribution<> dist(1000, 1ULL << 20);
    base = dist(rng);
  }

  int reg(string s) {
    int n = s.size();
    vector<u64> hs(n + 1);
    for (int i = 0; i < n; i++) {
      hs[i + 1] = calc_mod(mul(hs[i], base) + s[i]);
    }
    hash.push_back(move(hs));
    while ((int)pow_memo.size() < n + 1) {
      pow_memo.push_back(calc_mod(mul(pow_memo[pow_memo.size() - 1], base)));
    }
    return hash.size() - 1;
  }

  u64 get_hash(int idx, int start, int len) {
    return calc_mod(hash[idx][start + len] + positivizer -
                    mul(hash[idx][start], pow_memo[len]));
  }
};
random_device RollingHash::rand_dev;
mt19937 RollingHash::rng(RollingHash::rand_dev());

// ---- end rollingHash.cc
// @@ !! LIM  -- end mark --

int main(/* int argc, char *argv[] */) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << setprecision(20);

  using u64 = unsigned long long;

  RollingHash rh;

  ll N;
  cin >> N;
  vector<u64> init1(N);
  vector<char> last1(N);
  unordered_map<u64, unordered_map<char, ll>> mp;
  for (ll i = 0; i < N; i++) {
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    ll idx = rh.reg(s);
    ll sz = s.size();
    init1[i] = rh.get_hash(idx, 0, sz - 1);
    last1[i] = s[sz - 1];
    set<char> app;
    for (ll j = sz - 1; j >= 0; j--) {
      app.insert(s[j]);
      u64 hash = rh.get_hash(idx, 0, j);
      for (int c : app)
        mp[hash][c]++;
    }
  }
  ll ans = 0;
  for (ll i = 0; i < N; i++) {
    ans += mp[init1[i]][last1[i]] - 1;
  }

  cout << ans << endl;
  return 0;
}