Problem p02548 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

#define int long long
#define S second
#define F first
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define lb lower_bound
#define ub upper_bound
#define si(c) (int)((c).size())
#define lcm(a, b) (a * (b / __gcd(a, b)))
#define inf (int)(4e18)
#define endl '\\n'
#define mp make_pair
#define time(s) (double(clock() - s) / double(CLOCKS_PER_SEC))
#define debug(args...) _F(#args, args)
#define vi std::vector<int>
#define pii pair<int, int>
#define vpi vector<pii>
#define ordered_set                                                            \\
  tree<int, null_type, less<int>, rb_tree_tag,                                 \\
       tree_order_statistics_node_update>

clock_t start;
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

template <typename T> void _F(const char *name, T arg1) {
  cerr << name << " = " << arg1 << endl;
}
template <typename T, typename... Args>
void _F(const char *names, T arg1, Args... args) {
  const char *name = strchr(names, ',');
  cerr.write(names, name - names) << " = " << arg1 << endl;
  _F(name + 2, args...);
}

template <typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &q) {
  in >> q.F >> q.S;
  return in;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &out, pair<T1, T2> &q) {
  out << q.F << " " << q.S;
  return out;
}
template <typename T1, typename T2>
pair<T1, T2> operator+(pair<T1, T2> p1, pair<T1, T2> p2) {
  return {p1.F + p2.F, p1.S + p2.S};
}
template <typename T1, typename T2>
pair<T1, T2> operator-(pair<T1, T2> p1, pair<T1, T2> p2) {
  return {p1.F - p2.F, p1.S - p2.S};
}
template <typename T1, typename T2>
bool operator<(pair<T1, T2> p1, pair<T1, T2> p2) {
  return p1 < p2;
}

template <typename T> void Unique(vector<T> &v) {
  sort(all(v)), v.resize(distance(v.begin(), unique(all(v))));
}

const int N = 1e6 + 1;
int d[N];
void solve() {
  int n;
  cin >> n;

  int ans = 0;

  for (int i = 1; i <= n; i++) {
    for (int j = i; j <= n; j += i)
      d[j]++;
  }
  for (int i = 1; i < n; i++) {
    int cur = n - i;
    ans += d[cur];
  }
  cout << ans << endl;
}

signed main() {

  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  start = clock();

  int test = 1;
  // cin >> test;

  cout << fixed << setprecision(2);

  for (int i = 1; i <= test; ++i) {
    solve();
  }

  cerr << time(start);
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

#define int long long
#define S second
#define F first
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define lb lower_bound
#define ub upper_bound
#define si(c) (int)((c).size())
#define lcm(a, b) (a * (b / __gcd(a, b)))
#define inf (int)(4e18)
#define endl '\\n'
#define mp make_pair
#define time(s) (double(clock() - s) / double(CLOCKS_PER_SEC))
#define debug(args...) _F(#args, args)
#define vi std::vector<int>
#define pii pair<int, int>
#define vpi vector<pii>
#define ordered_set                                                            \\
  tree<int, null_type, less<int>, rb_tree_tag,                                 \\
       tree_order_statistics_node_update>

clock_t start;
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

template <typename T> void _F(const char *name, T arg1) {
  cerr << name << " = " << arg1 << endl;
}
template <typename T, typename... Args>
void _F(const char *names, T arg1, Args... args) {
  const char *name = strchr(names, ',');
  cerr.write(names, name - names) << " = " << arg1 << endl;
  _F(name + 2, args...);
}

template <typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &q) {
  in >> q.F >> q.S;
  return in;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &out, pair<T1, T2> &q) {
  out << q.F << " " << q.S;
  return out;
}
template <typename T1, typename T2>
pair<T1, T2> operator+(pair<T1, T2> p1, pair<T1, T2> p2) {
  return {p1.F + p2.F, p1.S + p2.S};
}
template <typename T1, typename T2>
pair<T1, T2> operator-(pair<T1, T2> p1, pair<T1, T2> p2) {
  return {p1.F - p2.F, p1.S - p2.S};
}
template <typename T1, typename T2>
bool operator<(pair<T1, T2> p1, pair<T1, T2> p2) {
  return p1 < p2;
}

template <typename T> void Unique(vector<T> &v) {
  sort(all(v)), v.resize(distance(v.begin(), unique(all(v))));
}

void solve() {
  int n;
  cin >> n;

  int ans = 0;
  for (int i = 1; i < n; i++) {
    int cur = n - i;

    for (int j = 1; j * j <= cur; j++) {
      if (cur % j == 0) {
        ans += (1 + (j != cur / j));
      }
    }
  }
  cout << ans << endl;
}

signed main() {

  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  start = clock();

#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
  freopen("error.txt", "w", stderr);
#endif

  int test = 1;
  // cin >> test;

  cout << fixed << setprecision(2);

  for (int i = 1; i <= test; ++i) {
    solve();
  }

  cerr << time(start);
  return 0;
}