Problem p02588 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>

using namespace std;

#define DEBUG(x) cerr << #x << ": " << x << endl;
#define DEBUG_VEC(v)                                                           \
  cerr << #v << ":";                                                           \
  for (int i = 0; i < v.size(); i++)                                           \
    cerr << " " << v[i];                                                       \
  cerr << endl;
#define DEBUG_MAT(v)                                                           \
  cerr << #v << endl;                                                          \
  for (int i = 0; i < v.size(); i++) {                                         \
    for (int j = 0; j < v[i].size(); j++) {                                    \
      cerr << v[i][j] << " ";                                                  \
    }                                                                          \
    cerr << endl;                                                              \
  }
typedef long long ll;
#define int ll

#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
template <class S, class T>
pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first + t.first, s.second + t.second);
}
template <class S, class T>
pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first - t.first, s.second - t.second);
}
template <class S, class T> ostream &operator<<(ostream &os, pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
#define X first
#define Y second
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rrep1(i, n) for (int i = (int)(n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(), c.end()
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout << setprecision(25) << fixed << p << endl;
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
// vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio()                                                                  \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
const ll MOD = 1000000007;
// const ll MOD = 998244353;
// #define mp make_pair
// #define endl '\n'

/*
struct dice {
  mt19937 mt;
  dice() : mt(chrono::steady_clock::now().time_since_epoch().count()) {}
  // [0, x)の一様乱数
  ll operator()(ll x) { return this->operator()(0, x); }
  // [x, y)の一様乱数
  ll operator()(ll x, ll y) {
    uniform_int_distribution<ll> dist(x, y - 1);
    return dist(mt);
  }
  vl operator()(int n, ll x, ll y) {
    vl res(n);
    for (int i = 0; i < n; i++) res[i] = this->operator()(x, y);
    return res;
  }
} rnd;

using ull = unsigned long long;
const ull MASK30 = (1UL << 30) - 1;
const ull MASK31 = (1UL << 31) - 1;
const ull M = (1UL << 61) - 1;
const ull B = rnd(2, M >> 1);
const ull POSITIVIZER = M * 3;;

class RollingHash {
public:

  vector<ull> hash;
  vector<ull> Bpower;

  RollingHash(string s) {
    int n = s.size();
    hash.resize(n + 1); Bpower.resize(n + 1);
    Bpower[0] = 1;

    for (int i = 0; i < n; i++) {
      hash[i + 1] = _calc_mod(_mul(hash[i], B) + s[i]);
      Bpower[i + 1] = _calc_mod(_mul(Bpower[i], B));
    }
  }

  //S[l, r)
  ull part(int l, int r) {
    return _calc_mod(hash[r] + POSITIVIZER - _mul(hash[l], Bpower[r - l]));
  }

  ull _mul(ull a, ull b) {
    ull au = a >> 31;
    ull ad = a & MASK31;
    ull bu = b >> 31;
    ull bd = b & MASK31;
    ull mid = ad * bu + au * bd;
    ull midu = mid >> 30;
    ull midd = mid & MASK30;
    return au * bu * 2 + midu + (midd << 31) + ad * bd;
  }

  ull _calc_mod(ull val) {
    val = (val & M) + (val >> 61);
    if (val > M) val -= M;
    return val;
  }
};


signed main() {
    fio();

    int n;
    cin >> n;
    vector<string> s(n);
    rep (i, n) cin >> s[i];
    sort(all(s), [](string &s1, string& s2) {
        return s1.size() < s2.size();
    });
    // DEBUG_VEC(s);

    vector<deque<char>> head(n);
    vector<deque<char>> tail(n);
    vector<RollingHash> hs;
    rep (i, n) {
        hs.push_back(RollingHash(s[i]));
    }

    vii num(n, vi(26));
    rep (i, n) {
        rep (j, s[i].size()) {
            head[i].push_back(s[i][j]);
            num[i][s[i][j] - 'a']++;
        }
    }

    map<ull, vi> mp;
    mp[0] = vi(26);
    int start_idx = -1;
    rep (i, n) {
        if (s[i].size() == 1) continue;
        if (start_idx == -1) start_idx = i;
        rep (j, 26) {
            if (num[i][j] > 0) mp[0][j]++;
        }
    }

    ll ans = 0;
    int i = 0;
    for (i = 0; i < n; i++) {
        if (s[i].size() == 1) {
            ans += mp[0][s[i][0] - 'a'];
        }
        else break;
    }

    int pre_len = 1;
    for (; i < n; i++) {
        if (s[i].size() > pre_len) {
            pre_len = s[i].size();
            while (s[start_idx].size() == s[i].size()) start_idx++;

            map<ull, vi> mp2;
            for (int j = start_idx; j < n; j++) {
                while (tail[j].size() < pre_len - 1) {
                    tail[j].push_front(head[j].back());
                    num[j][head[j].back() - 'a']--;
                    head[j].pop_back();
                }
                ull hash = hs[j].part((int)s[j].size() - (pre_len - 1),
s[j].size()); if (mp2.count(hash) == 0) mp2[hash] = vi(26); rep (k, 26) { if
(num[j][k] > 0) mp2[hash][k]++;
                }
            }
            swap(mp, mp2);
        }

        ull hash = hs[i].part(1, s[i].size());
        if (mp.count(hash)) {
            ans += mp[hash][s[i][0] - 'a'];
        }
    }
    cout << ans << endl;
}
//*/

//*
signed main() {
  fio();

  int n;
  cin >> n;

  vector<pii> tf;
  int mi2 = inf, mi5 = inf;
  int ma2 = -inf, ma5 = -inf;
  rep(i, n) {
    string s;
    cin >> s;
    ll bo = 1;
    rrep(i, s.size()) {
      if (s[i] == '.') {
        for (int j = i + 1; j < s.size(); j++)
          bo++;
        s.erase(s.begin() + i);
        break;
      }
    }
    ll si = stoll(s);
    // DEBUG(pll(si, bo));
    int two = 0, fi = 0;
    while (si > 0 and si % 2 == 0) {
      two++;
      si /= 2;
    }
    while (si > 0 and si % 5 == 0) {
      fi++;
      si /= 5;
    }
    two -= bo - 1;
    fi -= bo - 1;
    tf.push_back(pii(two, fi));
    chmin(mi2, two);
    chmin(mi5, fi);
    chmax(ma2, two);
    chmax(ma5, fi);
  }
  // DEBUG_VEC(tf);

  int N = 20;
  vii a(N, vi(N));
  rep(i, n) {
    int two = tf[i].first, fi = tf[i].second;
    a[two - mi2][fi - mi5]++;
  }

  vll sum(N + 1, vl(N + 1));
  rep(i, N) {
    rep(j, N) { sum[i + 1][j + 1] = sum[i + 1][j] + a[i][j]; }
  }
  rep(i, N) {
    rep(j, N + 1) { sum[i + 1][j] += sum[i][j]; }
  }
  // DEBUG_MAT(sum);

  ll ans = 0;
  rep(i, n) {
    int two = tf[i].first, fi = tf[i].second;
    if (tf[i].first >= 0 and tf[i].second >= 0)
      ans--;
    // DEBUG(ans);

    int ii = -two - mi2, jj = -fi - mi5;
    chmax(ii, 0LL);
    chmax(jj, 0LL);
    ans += sum[N][N] - sum[ii][N] - sum[N][jj] + sum[ii][jj];
    // DEBUG(ans);
  }
  assert(ans % 2 == 0);
  ans /= 2;
  cout << ans << endl;
}
//*/

Fixed submission:
#include <bits/stdc++.h>

using namespace std;

#define DEBUG(x) cerr << #x << ": " << x << endl;
#define DEBUG_VEC(v)                                                           \
  cerr << #v << ":";                                                           \
  for (int i = 0; i < v.size(); i++)                                           \
    cerr << " " << v[i];                                                       \
  cerr << endl;
#define DEBUG_MAT(v)                                                           \
  cerr << #v << endl;                                                          \
  for (int i = 0; i < v.size(); i++) {                                         \
    for (int j = 0; j < v[i].size(); j++) {                                    \
      cerr << v[i][j] << " ";                                                  \
    }                                                                          \
    cerr << endl;                                                              \
  }
typedef long long ll;
#define int ll

#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
template <class S, class T>
pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first + t.first, s.second + t.second);
}
template <class S, class T>
pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first - t.first, s.second - t.second);
}
template <class S, class T> ostream &operator<<(ostream &os, pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
#define X first
#define Y second
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rrep1(i, n) for (int i = (int)(n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(), c.end()
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout << setprecision(25) << fixed << p << endl;
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
// vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio()                                                                  \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
const ll MOD = 1000000007;
// const ll MOD = 998244353;
// #define mp make_pair
// #define endl '\n'

/*
struct dice {
  mt19937 mt;
  dice() : mt(chrono::steady_clock::now().time_since_epoch().count()) {}
  // [0, x)の一様乱数
  ll operator()(ll x) { return this->operator()(0, x); }
  // [x, y)の一様乱数
  ll operator()(ll x, ll y) {
    uniform_int_distribution<ll> dist(x, y - 1);
    return dist(mt);
  }
  vl operator()(int n, ll x, ll y) {
    vl res(n);
    for (int i = 0; i < n; i++) res[i] = this->operator()(x, y);
    return res;
  }
} rnd;

using ull = unsigned long long;
const ull MASK30 = (1UL << 30) - 1;
const ull MASK31 = (1UL << 31) - 1;
const ull M = (1UL << 61) - 1;
const ull B = rnd(2, M >> 1);
const ull POSITIVIZER = M * 3;;

class RollingHash {
public:

  vector<ull> hash;
  vector<ull> Bpower;

  RollingHash(string s) {
    int n = s.size();
    hash.resize(n + 1); Bpower.resize(n + 1);
    Bpower[0] = 1;

    for (int i = 0; i < n; i++) {
      hash[i + 1] = _calc_mod(_mul(hash[i], B) + s[i]);
      Bpower[i + 1] = _calc_mod(_mul(Bpower[i], B));
    }
  }

  //S[l, r)
  ull part(int l, int r) {
    return _calc_mod(hash[r] + POSITIVIZER - _mul(hash[l], Bpower[r - l]));
  }

  ull _mul(ull a, ull b) {
    ull au = a >> 31;
    ull ad = a & MASK31;
    ull bu = b >> 31;
    ull bd = b & MASK31;
    ull mid = ad * bu + au * bd;
    ull midu = mid >> 30;
    ull midd = mid & MASK30;
    return au * bu * 2 + midu + (midd << 31) + ad * bd;
  }

  ull _calc_mod(ull val) {
    val = (val & M) + (val >> 61);
    if (val > M) val -= M;
    return val;
  }
};


signed main() {
    fio();

    int n;
    cin >> n;
    vector<string> s(n);
    rep (i, n) cin >> s[i];
    sort(all(s), [](string &s1, string& s2) {
        return s1.size() < s2.size();
    });
    // DEBUG_VEC(s);

    vector<deque<char>> head(n);
    vector<deque<char>> tail(n);
    vector<RollingHash> hs;
    rep (i, n) {
        hs.push_back(RollingHash(s[i]));
    }

    vii num(n, vi(26));
    rep (i, n) {
        rep (j, s[i].size()) {
            head[i].push_back(s[i][j]);
            num[i][s[i][j] - 'a']++;
        }
    }

    map<ull, vi> mp;
    mp[0] = vi(26);
    int start_idx = -1;
    rep (i, n) {
        if (s[i].size() == 1) continue;
        if (start_idx == -1) start_idx = i;
        rep (j, 26) {
            if (num[i][j] > 0) mp[0][j]++;
        }
    }

    ll ans = 0;
    int i = 0;
    for (i = 0; i < n; i++) {
        if (s[i].size() == 1) {
            ans += mp[0][s[i][0] - 'a'];
        }
        else break;
    }

    int pre_len = 1;
    for (; i < n; i++) {
        if (s[i].size() > pre_len) {
            pre_len = s[i].size();
            while (s[start_idx].size() == s[i].size()) start_idx++;

            map<ull, vi> mp2;
            for (int j = start_idx; j < n; j++) {
                while (tail[j].size() < pre_len - 1) {
                    tail[j].push_front(head[j].back());
                    num[j][head[j].back() - 'a']--;
                    head[j].pop_back();
                }
                ull hash = hs[j].part((int)s[j].size() - (pre_len - 1),
s[j].size()); if (mp2.count(hash) == 0) mp2[hash] = vi(26); rep (k, 26) { if
(num[j][k] > 0) mp2[hash][k]++;
                }
            }
            swap(mp, mp2);
        }

        ull hash = hs[i].part(1, s[i].size());
        if (mp.count(hash)) {
            ans += mp[hash][s[i][0] - 'a'];
        }
    }
    cout << ans << endl;
}
//*/

//*
signed main() {
  fio();

  int n;
  cin >> n;

  vector<pii> tf;
  int mi2 = inf, mi5 = inf;
  int ma2 = -inf, ma5 = -inf;
  rep(i, n) {
    string s;
    cin >> s;
    ll bo = 1;
    rrep(i, s.size()) {
      if (s[i] == '.') {
        for (int j = i + 1; j < s.size(); j++)
          bo++;
        s.erase(s.begin() + i);
        break;
      }
    }
    ll si = stoll(s);
    // DEBUG(pll(si, bo));
    int two = 0, fi = 0;
    while (si > 0 and si % 2 == 0) {
      two++;
      si /= 2;
    }
    while (si > 0 and si % 5 == 0) {
      fi++;
      si /= 5;
    }
    two -= bo - 1;
    fi -= bo - 1;
    tf.push_back(pii(two, fi));
    chmin(mi2, two);
    chmin(mi5, fi);
    chmax(ma2, two);
    chmax(ma5, fi);
  }
  // DEBUG_VEC(tf);

  int N = 400;
  vii a(N, vi(N));
  rep(i, n) {
    int two = tf[i].first, fi = tf[i].second;
    a[two - mi2][fi - mi5]++;
  }

  vll sum(N + 1, vl(N + 1));
  rep(i, N) {
    rep(j, N) { sum[i + 1][j + 1] = sum[i + 1][j] + a[i][j]; }
  }
  rep(i, N) {
    rep(j, N + 1) { sum[i + 1][j] += sum[i][j]; }
  }
  // DEBUG_MAT(sum);

  ll ans = 0;
  rep(i, n) {
    int two = tf[i].first, fi = tf[i].second;
    if (tf[i].first >= 0 and tf[i].second >= 0)
      ans--;
    // DEBUG(ans);

    int ii = -two - mi2, jj = -fi - mi5;
    chmax(ii, 0LL);
    chmax(jj, 0LL);
    ans += sum[N][N] - sum[ii][N] - sum[N][jj] + sum[ii][jj];
    // DEBUG(ans);
  }
  assert(ans % 2 == 0);
  ans /= 2;
  cout << ans << endl;
}
//*/