Problem p02624 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cmath>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#ifdef LOCAL
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define eprintf(...) 42
#endif
using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
#define reps(i, S, E) for (ll i = (S); i <= (E); i++)
#define rep(i, N) reps(i, 0, N - 1)
#define deps(i, E, S) for (ll i = (E); i >= (S); i--)
#define dep(i, N) deps(i, N - 1, 0)
const ll INF = 1LL << 60;
const int INF_INT = 1 << 30;

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
struct mll {
  static ll MOD;
  ll val;
  mll(ll v = 0) : val(v % MOD) {
    if (val < 0)
      val += MOD;
  }
  mll operator-() const { return -val; }
  mll operator+(const mll &b) const { return val + b.val; }
  mll operator-(const mll &b) const { return val - b.val; }
  mll operator*(const mll &b) const { return val * b.val; }
  mll operator/(const mll &b) const { return mll(*this) /= b; }
  mll operator+(ll b) const { return *this + mll(b); }
  mll operator-(ll b) const { return *this - mll(b); }
  mll operator*(ll b) const { return *this * mll(b); }
  friend mll operator+(ll a, const mll &b) { return b + a; }
  friend mll operator-(ll a, const mll &b) { return -b + a; }
  friend mll operator*(ll a, const mll &b) { return b * a; }
  mll &operator+=(const mll &b) {
    val = (val + b.val) % MOD;
    return *this;
  }
  mll &operator-=(const mll &b) {
    val = (val + MOD - b.val) % MOD;
    return *this;
  }
  mll &operator*=(const mll &b) {
    val = (val * b.val) % MOD;
    return *this;
  }
  mll &operator/=(const mll &b) {
    ll c = b.val, d = MOD, u = 1, v = 0;
    while (d) {
      ll t = c / d;
      c -= t * d;
      swap(c, d);
      u -= t * v;
      swap(u, v);
    }
    val = val * u % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }
  mll &operator+=(ll b) { return *this += mll(b); }
  mll &operator-=(ll b) { return *this -= mll(b); }
  mll &operator*=(ll b) { return *this *= mll(b); }
  mll &operator/=(ll b) { return *this /= mll(b); }
  bool operator==(const mll &b) { return val == b.val; }
  bool operator!=(const mll &b) { return val != b.val; }
  bool operator==(ll b) { return *this == mll(b); }
  bool operator!=(ll b) { return *this != mll(b); }
  friend bool operator==(ll a, const mll &b) { return mll(a) == b.val; }
  friend bool operator!=(ll a, const mll &b) { return mll(a) != b.val; }
  friend ostream &operator<<(ostream &os, const mll &a) { return os << a.val; }
  friend istream &operator>>(istream &is, mll &a) { return is >> a.val; }
  static mll Combination(ll a, ll b) {
    chmin(b, a - b);
    if (b < 0)
      return mll(0);
    mll c = 1;
    rep(i, b) c *= a - i;
    rep(i, b) c /= i + 1;
    return c;
  }
};
using vmll = std::vector<mll>;
using vvmll = std::vector<vmll>;
using vvvmll = std::vector<vvmll>;
using vvvvmll = std::vector<vvvmll>;

struct Fast {
  Fast() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
  }
} fast; // cin,cout高速化のおまじない＋桁数指定

ll mll::MOD = (ll)(1e9 + 7); // 998244353ll;

vll diviser;
ll N;
vll prime;

void DecompositPrime(ll n, map<ll, ll> &result) {
  result.clear();
  ll a = 2;
  while (n >= a * a) {
    if (n % a == 0) {
      result[a]++;
      n /= a;
    } else {
      a++;
    }
  }
  if (n > 1) {
    result[n]++;
  }
}

bool Prime(ll x) {
  if (x == 1) {
    return false;
  }
  if (x == 2) {
    return true;
  }
  if (x % 2 == 0) {
    return false;
  }
  for (ll i = 3; i <= (ll)std::sqrt(x); i += 2) {
    if (x % i == 0) {
      return false;
    }
  }
  return true;
}

void rec(ll primeIndex, ll count, ll num) {
  ll c = 0;

  while (true) {

    if (primeIndex + 1 < prime.size()) {
      ll nextCount = count * (c + 1);
      rec(primeIndex + 1, nextCount, num);
    }

    num *= prime[primeIndex];
    c++;
    if (num > N) {
      break;
    }
    diviser[num] = count * (c + 1);
  }
}

void solve() {
  cin >> N;
  diviser.resize(N + 1, 0);

  reps(i, 1, N) {
    for (ll j = i; j <= N; j += i) {
      diviser[j]++;
    }
  }

  ll result = 0;

  reps(i, 1, N) { result += i * diviser[i]; }

  cout << result << endl;
}

int main() {
#if TEST && LOCAL
  ll t;
  cin >> t;
  rep(i, t) { solve(); }
#else
  solve();
#endif
  return 0;
}


Error: 0

Fixed submission:

#include <algorithm>
#include <cmath>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#ifdef LOCAL
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define eprintf(...) 42
#endif
using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
#define reps(i, S, E) for (ll i = (S); i <= (E); i++)
#define rep(i, N) reps(i, 0, N - 1)
#define deps(i, E, S) for (ll i = (E); i >= (S); i--)
#define dep(i, N) deps(i, N - 1, 0)
const ll INF = 1LL << 60;
const int INF_INT = 1 << 30;

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
struct mll {
  static ll MOD;
  ll val;
  mll(ll v = 0) : val(v % MOD) {
    if (val < 0)
      val += MOD;
  }
  mll operator-() const { return -val; }
  mll operator+(const mll &b) const { return val + b.val; }
  mll operator-(const mll &b) const { return val - b.val; }
  mll operator*(const mll &b) const { return val * b.val; }
  mll operator/(const mll &b) const { return mll(*this) /= b; }
  mll operator+(ll b) const { return *this + mll(b); }
  mll operator-(ll b) const { return *this - mll(b); }
  mll operator*(ll b) const { return *this * mll(b); }
  friend mll operator+(ll a, const mll &b) { return b + a; }
  friend mll operator-(ll a, const mll &b) { return -b + a; }
  friend mll operator*(ll a, const mll &b) { return b * a; }
  mll &operator+=(const mll &b) {
    val = (val + b.val) % MOD;
    return *this;
  }
  mll &operator-=(const mll &b) {
    val = (val + MOD - b.val) % MOD;
    return *this;
  }
  mll &operator*=(const mll &b) {
    val = (val * b.val) % MOD;
    return *this;
  }
  mll &operator/=(const mll &b) {
    ll c = b.val, d = MOD, u = 1, v = 0;
    while (d) {
      ll t = c / d;
      c -= t * d;
      swap(c, d);
      u -= t * v;
      swap(u, v);
    }
    val = val * u % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }
  mll &operator+=(ll b) { return *this += mll(b); }
  mll &operator-=(ll b) { return *this -= mll(b); }
  mll &operator*=(ll b) { return *this *= mll(b); }
  mll &operator/=(ll b) { return *this /= mll(b); }
  bool operator==(const mll &b) { return val == b.val; }
  bool operator!=(const mll &b) { return val != b.val; }
  bool operator==(ll b) { return *this == mll(b); }
  bool operator!=(ll b) { return *this != mll(b); }
  friend bool operator==(ll a, const mll &b) { return mll(a) == b.val; }
  friend bool operator!=(ll a, const mll &b) { return mll(a) != b.val; }
  friend ostream &operator<<(ostream &os, const mll &a) { return os << a.val; }
  friend istream &operator>>(istream &is, mll &a) { return is >> a.val; }
  static mll Combination(ll a, ll b) {
    chmin(b, a - b);
    if (b < 0)
      return mll(0);
    mll c = 1;
    rep(i, b) c *= a - i;
    rep(i, b) c /= i + 1;
    return c;
  }
};
using vmll = std::vector<mll>;
using vvmll = std::vector<vmll>;
using vvvmll = std::vector<vvmll>;
using vvvvmll = std::vector<vvvmll>;

struct Fast {
  Fast() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
  }
} fast; // cin,cout高速化のおまじない＋桁数指定

ll mll::MOD = (ll)(1e9 + 7); // 998244353ll;

vll diviser;
ll N;
vll prime;

void DecompositPrime(ll n, map<ll, ll> &result) {
  result.clear();
  ll a = 2;
  while (n >= a * a) {
    if (n % a == 0) {
      result[a]++;
      n /= a;
    } else {
      a++;
    }
  }
  if (n > 1) {
    result[n]++;
  }
}

bool Prime(ll x) {
  if (x == 1) {
    return false;
  }
  if (x == 2) {
    return true;
  }
  if (x % 2 == 0) {
    return false;
  }
  for (ll i = 3; i <= (ll)std::sqrt(x); i += 2) {
    if (x % i == 0) {
      return false;
    }
  }
  return true;
}

void rec(ll primeIndex, ll count, ll num) {
  ll c = 0;

  while (true) {

    if (primeIndex + 1 < prime.size()) {
      ll nextCount = count * (c + 1);
      rec(primeIndex + 1, nextCount, num);
    }

    num *= prime[primeIndex];
    c++;
    if (num > N) {
      break;
    }
    diviser[num] = count * (c + 1);
  }
}

void solve() {
  cin >> N;
  diviser.resize(N * 2, 0);

  reps(i, 2, N) {
    if (Prime(i)) {
      prime.push_back(i);
    }
  }

  rec(0, 1, 1);

  diviser[1] = 1;

  ll result = 0;

  map<ll, ll> mp;
  reps(i, 1, N) {
    if (diviser[i] > 0) {
      result += i * diviser[i];
      continue;
    }

    DecompositPrime(i, mp);

    ll ans = 1;
    auto begin = mp.begin(), end = mp.end();
    for (auto iter = begin; iter != end; iter++) {
      // iter->first: key, iter->second: value
      ans *= (iter->second + 1);
    }

    diviser[i] = ans;
    result += i * diviser[i];
  }

  // reps(i, 0, N) {
  //	cout << diviser[i] << ",";
  // }

  cout << result << endl;
}

int main() {
#if TEST && LOCAL
  ll t;
  cin >> t;
  rep(i, t) { solve(); }
#else
  solve();
#endif
  return 0;
}