Problem p02588 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
#define dump(x)                                                                \
  if (dbg) {                                                                   \
    cerr << #x << " = " << (x) << endl;                                        \
  }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
namespace mydef {
const int INF = 1ll << 60;
const int MOD = 1e9 + 7;
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  } else
    return 0;
}
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  } else
    return 0;
}
void Yes(bool flag = true) {
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
void No(bool flag = true) { Yes(!flag); }
void YES(bool flag = true) {
  if (flag)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
}
void NO(bool flag = true) { YES(!flag); }
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
  std::fill((T *)array, (T *)(array + N), val);
}
bool dbg = false;
} // namespace mydef
using namespace mydef;
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vp vector<pair<int, int>>
#define vvp vector<vector<pair<int, int>>>
#define pi pair<int, int>
// #define P pair<int, int>
// #define V vector<int>
// #define S set<int>
#define asn ans

int N;
vector<pi> A;

int intpow(int a, int b) {
  int ans = 1;
  while (b) {
    if (b & 1)
      ans *= a;
    a *= a;
    b /= 2;
  }
  return ans;
}

pi f(string s) {
  int check = -1;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '.') {
      check = i;
      break;
    }
  }
  if (check < 0) {
    return pi(atoll(s.c_str()), 1);
  } else {
    int n = s.size() - check - 1;
    int se = intpow(10, n);
    s.erase(check, 1);
    int fi = atoll(s.c_str());
    while (fi % 2 == 0 && se % 2 == 0) {
      fi /= 2;
      se /= 2;
    }
    while (fi % 5 == 0 && se % 5 == 0) {
      fi /= 5;
      se /= 5;
    }
    return pi(fi, se);
  }
}

pi g(int x) {
  int t2 = 0, t5 = 0;
  while (x % 2 == 0) {
    x /= 2;
    t2++;
  }
  while (x % 5 == 0) {
    x /= 5;
    t5++;
  }
  return pi(t2, t5);
}

int cnt_fi[100][100];
int cnt_se[100][100];

int cnt[10][100][100];

void solve() {
  int ans = 0;
  for (auto &p : A) {
    int fi = p.first;
    int se = p.second;
    pi P_se, P_fi;

    P_se = g(se);
    cnt_se[P_se.first][P_se.second]++;
    P_fi = g(fi);
    cnt_fi[P_fi.first][P_fi.second]++;

    for (int i = 0; i < 65; i++) {
      for (int j = 0; j < 25; j++) {
        if (i >= P_se.first && j >= P_se.second) {
          ans += cnt[1][i][j];
        }
        if (i >= P_se.first && j <= P_fi.second)
          ans += cnt[2][i][j];
        if (i <= P_fi.first && j >= P_se.second)
          ans += cnt[3][i][j];
        if (i <= P_fi.first && j <= P_fi.second)
          ans += cnt[4][i][j];
      }
    }

    cerr << fi << " " << se << " : " << ans << endl;

    if (P_se.first && P_se.second) {
      cnt[4][P_se.first][P_se.second]++;
    } else if (P_se.first && !P_se.second) {
      cnt[3][P_se.first][P_fi.second]++;
    } else if (!P_se.first && P_se.second) {
      cnt[2][P_fi.first][P_se.second]++;
    } else
      cnt[1][P_fi.first][P_fi.second]++;
  }
  cout << ans << endl;
}

signed main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  cin >> N;
  A.resize(N);
  for (int i = 0; i < N; i++) {
    string s;
    cin >> s;
    A[i] = f(s);
  }

  solve();
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
#define dump(x)                                                                \
  if (dbg) {                                                                   \
    cerr << #x << " = " << (x) << endl;                                        \
  }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
namespace mydef {
const int INF = 1ll << 60;
const int MOD = 1e9 + 7;
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  } else
    return 0;
}
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  } else
    return 0;
}
void Yes(bool flag = true) {
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
void No(bool flag = true) { Yes(!flag); }
void YES(bool flag = true) {
  if (flag)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
}
void NO(bool flag = true) { YES(!flag); }
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
  std::fill((T *)array, (T *)(array + N), val);
}
bool dbg = false;
} // namespace mydef
using namespace mydef;
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vp vector<pair<int, int>>
#define vvp vector<vector<pair<int, int>>>
#define pi pair<int, int>
// #define P pair<int, int>
// #define V vector<int>
// #define S set<int>
#define asn ans

int N;
vector<pi> A;

int intpow(int a, int b) {
  int ans = 1;
  while (b) {
    if (b & 1)
      ans *= a;
    a *= a;
    b /= 2;
  }
  return ans;
}

pi f(string s) {
  int check = -1;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '.') {
      check = i;
      break;
    }
  }
  if (check < 0) {
    return pi(atoll(s.c_str()), 1);
  } else {
    int n = s.size() - check - 1;
    int se = intpow(10, n);
    s.erase(check, 1);
    int fi = atoll(s.c_str());
    while (fi % 2 == 0 && se % 2 == 0) {
      fi /= 2;
      se /= 2;
    }
    while (fi % 5 == 0 && se % 5 == 0) {
      fi /= 5;
      se /= 5;
    }
    return pi(fi, se);
  }
}

pi g(int x) {
  int t2 = 0, t5 = 0;
  while (x % 2 == 0) {
    x /= 2;
    t2++;
  }
  while (x % 5 == 0) {
    x /= 5;
    t5++;
  }
  return pi(t2, t5);
}

int cnt_fi[100][100];
int cnt_se[100][100];

int cnt[10][100][100];

void solve() {
  int ans = 0;
  for (auto &p : A) {
    int fi = p.first;
    int se = p.second;
    pi P_se, P_fi;

    P_se = g(se);
    cnt_se[P_se.first][P_se.second]++;
    P_fi = g(fi);
    cnt_fi[P_fi.first][P_fi.second]++;

    for (int i = 0; i < 65; i++) {
      for (int j = 0; j < 25; j++) {
        if (i >= P_se.first && j >= P_se.second) {
          ans += cnt[1][i][j];
        }
        if (i >= P_se.first && j <= P_fi.second)
          ans += cnt[2][i][j];
        if (i <= P_fi.first && j >= P_se.second)
          ans += cnt[3][i][j];
        if (i <= P_fi.first && j <= P_fi.second)
          ans += cnt[4][i][j];
      }
    }

    if (P_se.first && P_se.second) {
      cnt[4][P_se.first][P_se.second]++;
    } else if (P_se.first && !P_se.second) {
      cnt[3][P_se.first][P_fi.second]++;
    } else if (!P_se.first && P_se.second) {
      cnt[2][P_fi.first][P_se.second]++;
    } else
      cnt[1][P_fi.first][P_fi.second]++;
  }
  cout << ans << endl;
}

signed main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  cin >> N;
  A.resize(N);
  for (int i = 0; i < N; i++) {
    string s;
    cin >> s;
    A[i] = f(s);
  }

  solve();
  return 0;
}