Problem p02624 (C++)

Buggy submission (status: Time Limit Exceeded):
/*input

*/

// assic value of ('0'-'9') is(48 - 57) and (a-z) is (97-122) and (A-Z)
// is(65-90) and 32 for space #pragma GCC target ("avx2") #pragma GCC
// optimization ("O3") #pragma GCC optimization ("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;

// order_of_key (k) : Number of items strictly smaller than k .
// find_by_order(k) : K-th element in a set (counting from zero).
using namespace __gnu_pbds;
template <class T>
using oset =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define ll long long int
#define pb push_back
#define pii pair<ll, ll>
#define vpii vector<pii>
#define vi vector<ll>
#define vs vector<string>
#define vvi vector<vector<ll>>
#define inf (ll)1e18
#define all(it, a) for (auto it = (a).begin(); it != (a).end(); it++)
#define F first
#define S second
#define sz(x) (ll) x.size()
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define repr(i, a, b) for (ll i = a; i > b; i--)
#define lbnd lower_bound
#define ubnd upper_bound
#define mp make_pair
#define whatis(x) cout << #x << " is " << x << "\n";
#define graph(n) adj(n, vector<ll>())
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

#define debug(x) cout << #x << " " << x << endl;
#define debug_p(x) cout << #x << " " << x.F << " " << x.S << endl;
#define debug_v(x)                                                             \
  {                                                                            \
    cout << #x << " ";                                                         \
    for (auto ioi : x)                                                         \
      cout << ioi << " ";                                                      \
    cout << endl;                                                              \
  }
#define debug_vp(x)                                                            \
  {                                                                            \
    cout << #x << " ";                                                         \
    for (auto ioi : x)                                                         \
      cout << '[' << ioi.F << " " << ioi.S << ']';                             \
    cout << endl;                                                              \
  }
#define debug_v_v(x)                                                           \
  {                                                                            \
    cout << #x << "/*\n";                                                      \
    for (auto ioi : x) {                                                       \
      for (auto ioi2 : ioi)                                                    \
        cout << ioi2 << " ";                                                   \
      cout << '\n';                                                            \
    }                                                                          \
    cout << "*/" << #x << endl;                                                \
  }
const ll N = 1e7 + 5;
vi spd(N, -1);
void init() {
  rep(i, 2, N) {
    if (spd[i] == -1) {
      spd[i] = i;
      for (ll j = i * i; j < N; j += i)
        if (spd[j] == -1)
          spd[j] = i;
    }
  }
  return;
}

int solve() {
  init();
  ll n;
  cin >> n;
  ll ans = 1;
  rep(i, 2, n + 1) {
    unordered_map<ll, ll> cnt;
    ll temp = 1;
    ll dup = i;
    while (dup > 1)
      cnt[spd[dup]]++, dup /= spd[dup];
    all(it, cnt) temp *= (it->S + 1);
    ans = ans + i * temp;
  }

  cout << ans << "\n";
  return 0;
}

int main() {
  auto start = chrono::high_resolution_clock::now();

  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  ll test_cases = 1;
  // cin>>test_cases;
  while (test_cases--)
    solve();

  auto stop = chrono::high_resolution_clock::now();
  auto duration = chrono::duration_cast<chrono::milliseconds>(stop - start);
  // cout<<"\nduration: "<<(double)duration.count()<<" milliseconds";
}

Fixed submission:
/*input

*/

// assic value of ('0'-'9') is(48 - 57) and (a-z) is (97-122) and (A-Z)
// is(65-90) and 32 for space #pragma GCC target ("avx2") #pragma GCC
// optimization ("O3") #pragma GCC optimization ("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;

// order_of_key (k) : Number of items strictly smaller than k .
// find_by_order(k) : K-th element in a set (counting from zero).
using namespace __gnu_pbds;
template <class T>
using oset =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define ll long long int
#define pb push_back
#define pii pair<ll, ll>
#define vpii vector<pii>
#define vi vector<ll>
#define vs vector<string>
#define vvi vector<vector<ll>>
#define inf (ll)1e18
#define all(it, a) for (auto it = (a).begin(); it != (a).end(); it++)
#define F first
#define S second
#define sz(x) (ll) x.size()
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define repr(i, a, b) for (ll i = a; i > b; i--)
#define lbnd lower_bound
#define ubnd upper_bound
#define mp make_pair
#define whatis(x) cout << #x << " is " << x << "\n";
#define graph(n) adj(n, vector<ll>())
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

#define debug(x) cout << #x << " " << x << endl;
#define debug_p(x) cout << #x << " " << x.F << " " << x.S << endl;
#define debug_v(x)                                                             \
  {                                                                            \
    cout << #x << " ";                                                         \
    for (auto ioi : x)                                                         \
      cout << ioi << " ";                                                      \
    cout << endl;                                                              \
  }
#define debug_vp(x)                                                            \
  {                                                                            \
    cout << #x << " ";                                                         \
    for (auto ioi : x)                                                         \
      cout << '[' << ioi.F << " " << ioi.S << ']';                             \
    cout << endl;                                                              \
  }
#define debug_v_v(x)                                                           \
  {                                                                            \
    cout << #x << "/*\n";                                                      \
    for (auto ioi : x) {                                                       \
      for (auto ioi2 : ioi)                                                    \
        cout << ioi2 << " ";                                                   \
      cout << '\n';                                                            \
    }                                                                          \
    cout << "*/" << #x << endl;                                                \
  }
const ll N = 1e7 + 5;
vi spd(N, -1);
void init() {
  rep(i, 2, N) {
    if (spd[i] == -1) {
      spd[i] = i;
      for (ll j = i * i; j < N; j += i)
        if (spd[j] == -1)
          spd[j] = i;
    }
  }
  return;
}

int solve() {
  init();
  ll n;
  cin >> n;
  ll ans = 0;
  vi cnt(n + 1, 0);
  rep(i, 1, n + 1) for (ll j = i; j <= n; j += i) cnt[j]++;
  rep(i, 1, n + 1) ans += i * cnt[i];
  cout << ans << "\n";
  return 0;
}

int main() {
  auto start = chrono::high_resolution_clock::now();

  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  ll test_cases = 1;
  // cin>>test_cases;
  while (test_cases--)
    solve();

  auto stop = chrono::high_resolution_clock::now();
  auto duration = chrono::duration_cast<chrono::milliseconds>(stop - start);
  // cout<<"\nduration: "<<(double)duration.count()<<" milliseconds";
}