Problem p02793 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;

// 変数ダンプ先。coutかcerr
#define DUMPOUT cerr

// 提出時はコメントアウト
#define DEBUG_

// #define int long long // intで書いたけど心配なときにlong longに変換する
struct Fast {
  Fast() {
    std::cin.tie(0);
    ios::sync_with_stdio(false);
  }
} fast;

/* cpp template {{{ */

/* short */
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define Fi first
#define Se second
#define ALL(v) begin(v), end(v)
#define RALL(v) rbegin(v), rend(v)
#define X real()
#define Y imag()

/* REPmacro */
#define REPS(i, a, n) for (ll i = (a); i < (ll)(n); ++i)
#define REP(i, n) REPS(i, 0, n)
#define RREP(i, n) REPS(i, 1, n + 1)
#define DEPS(i, a, n) for (ll i = (a); i >= (ll)(n); --i)
#define DEP(i, n) DEPS(i, n, 0)
#define EACH(i, n) for (auto &&i : n)

/* debug */
#define debug(x)                                                               \
  cerr << x << " "                                                             \
       << "(L:" << __LINE__ << ")" << '\n';

/* alias */
using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using pii = pair<int, int>;
using D = double;
using P = complex<D>;
using vs = vector<string>;
template <typename T> using PQ = priority_queue<T>;
template <typename T> using minPQ = priority_queue<T, vector<T>, greater<T>>;

/* const */
const int INF = 1001001001;
const ll LINF = 1001001001001001001ll;
const int MOD = 1e9 + 7;
const D EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1},
          dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool inside(int y, int x, int H, int W) {
  return y >= 0 && x >= 0 && y < H && x < W;
}
inline int in() {
  int x;
  cin >> x;
  return x;
}
inline ll IN() {
  ll x;
  cin >> x;
  return x;
}
inline vs split(const string &t, char c) {
  vs v;
  stringstream s(t);
  string b;
  while (getline(s, b, c))
    v.eb(b);
  return v;
}
template <typename T> inline bool chmin(T &a, const T &b) {
  if (a > b)
    a = b;
  return a > b;
}
template <typename T> inline bool chmax(T &a, const T &b) {
  if (a < b)
    a = b;
  return a < b;
}
template <typename T, typename S> inline void print(const pair<T, S> &p) {
  cout << p.first << " " << p.second << endl;
}
template <typename T> inline void print(const T &x) { cout << x << '\n'; }
template <typename T, typename S>
inline void print(const vector<pair<T, S>> &v) {
  for (auto &&p : v)
    print(p);
}
template <typename T> inline void print(const vector<T> &v, string s = " ") {
  REP(i, v.size()) cout << v[i] << (i != (ll)v.size() - 1 ? s : "\n");
}
// clang-format on
/* }}} */

#ifdef DEBUG_
#define DEB
#else
// DEB と打つとデバッグ時以外はコメントアウトになる
#define DEB / ## /
#endif

// 変数ダンプ用マクロ。デバッグ時以外は消滅する
// 引数はいくつでもどんな型でも可（ストリーム出力演算子があればOK）
#define dump(...)                                                              \
  DEB DUMPOUT << "  ";                                                         \
  DUMPOUT << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]"   \
          << endl;                                                             \
  DUMPOUT << "    ";                                                           \
  dump_func(__VA_ARGS__)

// デバッグ用変数ダンプ関数
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) == 0) {
    DUMPOUT << " ";
  } else {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
}

// vector出力
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  os << "{";
  for (int i = 0; i < vec.size(); i++) {
    os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
  }
  os << "}";
  return os;
}

ll mod = 1000000007;

ll modplus(ll x, ll y) { return (x + y) % mod; }

ll modminus(ll x, ll y) { return (x - y + mod) % mod; }

ll multiply(ll x, ll y) { return (x % mod) * (y % mod) % mod; }

ll power(ll x, ll y) {
  if (y == 0) {
    return 1;
  } else if (y == 1) {
    return x % mod;
  } else if (y % 2 == 0) {
    ll p = power(x, y / 2);
    return p * p % mod;
  } else {
    ll p = power(x, y / 2);
    return (p * p) % mod * (x % mod) % mod;
  }
}

ll divide(ll x, ll y) { return multiply(x, power(y, mod - 2)); }

// 「オイラーのふるい」。pnには素数の数が、primesには順番に素数が、
// eulnumsにはその整数を割り切る最小の素数が入る。
// ある数からeulnumsを割っていくとその数の素因数分解が可能。
int pn = 0;
int primes[16000000];
int eulnums[16000000];

void eulerprime(int n) {
  fill(eulnums, eulnums + n + 1, 0);
  for (int i = 2; i <= n; i++) {
    if (eulnums[i] == 0) {
      eulnums[i] = i;
      primes[pn] = i;
      pn++;
    }

    for (int j = 0; i * primes[j] <= n; j++) {
      eulnums[i * primes[j]] = primes[j];
      if (i % primes[j] == 0) {
        break;
      }
    }
  }
}

signed main() {
  ll N;
  cin >> N;
  vector<int> A(N);
  REP(i, N) cin >> A[i];
  eulerprime(1000000);

  int my_factor[pn];
  int lcm_factor[pn];

  REP(i, pn) { lcm_factor[i] = 0; }

  int a, d;
  REP(i, N) {
    REP(i, pn) { my_factor[i] = 0; }
    a = A[i];
    while (a > 1) {
      d = eulnums[a];
      REP(j, pn) {
        if (d == primes[j]) {
          my_factor[j]++;
        }
      }
      a /= d;
    }
    REP(i, pn) { lcm_factor[i] = max(lcm_factor[i], my_factor[i]); }
  }

  ll ans = 0;
  ll LCM = 1;
  REP(i, pn) {
    if (lcm_factor[i] > 0) {
      REP(j, lcm_factor[i]) { LCM = multiply(LCM, primes[i]); }
    }
  }
  // cout << LCM << endl;  // DEBUG
  REP(i, N) { ans = modplus(ans, divide(LCM, A[i])); }
  cout << ans << endl;
}

// https://github.com/kurokoji/.cpp-Template/wiki テンプレートについて
// http://www.creativ.xyz/dump-cpp-652 dump()について
// https://gist.github.com/rigibun/7905920 色々

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

// 変数ダンプ先。coutかcerr
#define DUMPOUT cerr

// 提出時はコメントアウト
#define DEBUG_

// #define int long long // intで書いたけど心配なときにlong longに変換する
struct Fast {
  Fast() {
    std::cin.tie(0);
    ios::sync_with_stdio(false);
  }
} fast;

/* cpp template {{{ */

/* short */
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define Fi first
#define Se second
#define ALL(v) begin(v), end(v)
#define RALL(v) rbegin(v), rend(v)
#define X real()
#define Y imag()

/* REPmacro */
#define REPS(i, a, n) for (ll i = (a); i < (ll)(n); ++i)
#define REP(i, n) REPS(i, 0, n)
#define RREP(i, n) REPS(i, 1, n + 1)
#define DEPS(i, a, n) for (ll i = (a); i >= (ll)(n); --i)
#define DEP(i, n) DEPS(i, n, 0)
#define EACH(i, n) for (auto &&i : n)

/* debug */
#define debug(x)                                                               \
  cerr << x << " "                                                             \
       << "(L:" << __LINE__ << ")" << '\n';

/* alias */
using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using pii = pair<int, int>;
using D = double;
using P = complex<D>;
using vs = vector<string>;
template <typename T> using PQ = priority_queue<T>;
template <typename T> using minPQ = priority_queue<T, vector<T>, greater<T>>;

/* const */
const int INF = 1001001001;
const ll LINF = 1001001001001001001ll;
const int MOD = 1e9 + 7;
const D EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1},
          dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool inside(int y, int x, int H, int W) {
  return y >= 0 && x >= 0 && y < H && x < W;
}
inline int in() {
  int x;
  cin >> x;
  return x;
}
inline ll IN() {
  ll x;
  cin >> x;
  return x;
}
inline vs split(const string &t, char c) {
  vs v;
  stringstream s(t);
  string b;
  while (getline(s, b, c))
    v.eb(b);
  return v;
}
template <typename T> inline bool chmin(T &a, const T &b) {
  if (a > b)
    a = b;
  return a > b;
}
template <typename T> inline bool chmax(T &a, const T &b) {
  if (a < b)
    a = b;
  return a < b;
}
template <typename T, typename S> inline void print(const pair<T, S> &p) {
  cout << p.first << " " << p.second << endl;
}
template <typename T> inline void print(const T &x) { cout << x << '\n'; }
template <typename T, typename S>
inline void print(const vector<pair<T, S>> &v) {
  for (auto &&p : v)
    print(p);
}
template <typename T> inline void print(const vector<T> &v, string s = " ") {
  REP(i, v.size()) cout << v[i] << (i != (ll)v.size() - 1 ? s : "\n");
}
// clang-format on
/* }}} */

#ifdef DEBUG_
#define DEB
#else
// DEB と打つとデバッグ時以外はコメントアウトになる
#define DEB / ## /
#endif

// 変数ダンプ用マクロ。デバッグ時以外は消滅する
// 引数はいくつでもどんな型でも可（ストリーム出力演算子があればOK）
#define dump(...)                                                              \
  DEB DUMPOUT << "  ";                                                         \
  DUMPOUT << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]"   \
          << endl;                                                             \
  DUMPOUT << "    ";                                                           \
  dump_func(__VA_ARGS__)

// デバッグ用変数ダンプ関数
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) == 0) {
    DUMPOUT << " ";
  } else {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
}

// vector出力
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  os << "{";
  for (int i = 0; i < vec.size(); i++) {
    os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
  }
  os << "}";
  return os;
}

ll mod = 1000000007;

ll modplus(ll x, ll y) { return (x + y) % mod; }

ll modminus(ll x, ll y) { return (x - y + mod) % mod; }

ll multiply(ll x, ll y) { return (x % mod) * (y % mod) % mod; }

ll power(ll x, ll y) {
  if (y == 0) {
    return 1;
  } else if (y == 1) {
    return x % mod;
  } else if (y % 2 == 0) {
    ll p = power(x, y / 2);
    return p * p % mod;
  } else {
    ll p = power(x, y / 2);
    return (p * p) % mod * (x % mod) % mod;
  }
}

ll divide(ll x, ll y) { return multiply(x, power(y, mod - 2)); }

// 「オイラーのふるい」。pnには素数の数が、primesには順番に素数が、
// eulnumsにはその整数を割り切る最小の素数が入る。
// ある数からeulnumsを割っていくとその数の素因数分解が可能。
int pn = 0;
int primes[16000000];
int eulnums[16000000];

void eulerprime(int n) {
  fill(eulnums, eulnums + n + 1, 0);
  for (int i = 2; i <= n; i++) {
    if (eulnums[i] == 0) {
      eulnums[i] = i;
      primes[pn] = i;
      pn++;
    }

    for (int j = 0; i * primes[j] <= n; j++) {
      eulnums[i * primes[j]] = primes[j];
      if (i % primes[j] == 0) {
        break;
      }
    }
  }
}

signed main() {
  ll N;
  cin >> N;
  vector<int> A(N);
  REP(i, N) cin >> A[i];
  eulerprime(1000000);

  int my_factor[pn];
  int lcm_factor[pn];

  REP(i, pn) { lcm_factor[i] = 0; }

  int a, d;
  REP(i, N) {
    REP(i, pn) { my_factor[i] = 0; }
    a = A[i];
    while (a > 1) {
      d = eulnums[a];
      REP(j, pn) {
        if (d == primes[j]) {
          my_factor[j]++;
          break;
        }
      }
      a /= d;
    }
    REP(i, pn) { lcm_factor[i] = max(lcm_factor[i], my_factor[i]); }
  }

  ll ans = 0;
  ll LCM = 1;
  REP(i, pn) {
    if (lcm_factor[i] > 0) {
      REP(j, lcm_factor[i]) { LCM = multiply(LCM, primes[i]); }
    }
  }
  // cout << LCM << endl;  // DEBUG
  REP(i, N) { ans = modplus(ans, divide(LCM, A[i])); }
  cout << ans << endl;
}

// https://github.com/kurokoji/.cpp-Template/wiki テンプレートについて
// http://www.creativ.xyz/dump-cpp-652 dump()について
// https://gist.github.com/rigibun/7905920 色々