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

constexpr bool isDebugMode = false;
int testcase = 1;
#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
using namespace std;
typedef long long ll;
typedef pair<long long, long long> P;
struct edge {
  long long to, cost;
};
const int inf = 1 << 27;
const long long INF = 1LL << 60;
const int COMBMAX = 1001001;
const long long MOD = 1000000007; // 998244353;
const long long dy[] = {-1, 0, 0, 1};
const long long dx[] = {0, -1, 1, 0};
const string abc = "abcdefghijklmnopqrstuvwxyz";
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define eachdo(v, e) for (const auto &e : (v))
#define all(v) (v).begin(), (v).end()
#define lower_index(v, e)                                                      \\
  (long long)distance((v).begin(), lower_bound((v).begin(), (v).end(), e))
#define upper_index(v, e)                                                      \\
  (long long)distance((v).begin(), upper_bound((v).begin(), (v).end(), e))
long long mpow(long long a, long long n, long long mod = MOD) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
void pt() {
  cout << endl;
  return;
}
template <class Head> void pt(Head &&head) {
  cout << head;
  pt();
  return;
}
template <class Head, class... Tail> void pt(Head &&head, Tail &&...tail) {
  cout << head << " ";
  pt(forward<Tail>(tail)...);
}
void dpt() {
  if (!isDebugMode)
    return;
  cout << endl;
  return;
}
template <class Head> void dpt(Head &&head) {
  if (!isDebugMode)
    return;
  cout << head;
  pt();
  return;
}
template <class Head, class... Tail> void dpt(Head &&head, Tail &&...tail) {
  if (!isDebugMode)
    return;
  cout << head << " ";
  pt(forward<Tail>(tail)...);
}
template <class T> void enu(T v) {
  rep(i, v.size()) cout << v[i] << " ";
  cout << endl;
}
template <class T> void enu2(T v) {
  rep(i, v.size()) {
    rep(j, v[i].size()) cout << v[i][j] << " ";
    cout << endl;
  }
}
template <class T> void debug(T v) {
  if (!isDebugMode)
    return;
  rep(i, v.size()) cout << v[i] << " ";
  cout << endl;
}
template <class T> void debug2(T v) {
  if (!isDebugMode)
    return;
  rep(i, v.size()) {
    rep(j, v[i].size()) cout << v[i][j] << " ";
    cout << endl;
  }
}
template <class T1, class T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2> long long recgcd(T1 a, T2 b) {
  return a % b ? recgcd(b, a % b) : b;
}
bool valid(long long H, long long W, long long h, long long w) {
  return 0 <= h && h < H && 0 <= w && w < W;
}

void solve();

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  // cin >> testcase;
  while (testcase--)
    solve();
  return 0;
}

void solve() {
  ll N;
  cin >> N;
  ll ans = 0;
  vector<ll> list(N + 1);
  rep(i, N + 1) list[i] = i;
  for (ll i = 2; i <= N; i++) {
    if (list[i] == i) {
      for (ll j = i; j <= N; j += i) {
        list[j] = i;
      }
    }
  }
  // enu(list);
  for (ll c = 1; c <= N - 1; c++) {
    ll num = N - c;
    map<ll, ll> ds;
    for (; num > 1;) {
      ds[list[num]]++;
      num /= list[num];
    }
    ll tem = 1;
    for (auto &e : ds)
      tem *= e.second + 1;
    ans += tem;
  }
  pt(ans);
}

Error: TLE

Fixed submission:

constexpr bool isDebugMode = false;
int testcase = 1;
#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
using namespace std;
typedef long long ll;
typedef pair<long long, long long> P;
struct edge {
  long long to, cost;
};
const int inf = 1 << 27;
const long long INF = 1LL << 60;
const int COMBMAX = 1001001;
const long long MOD = 1000000007; // 998244353;
const long long dy[] = {-1, 0, 0, 1};
const long long dx[] = {0, -1, 1, 0};
const string abc = "abcdefghijklmnopqrstuvwxyz";
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define eachdo(v, e) for (const auto &e : (v))
#define all(v) (v).begin(), (v).end()
#define lower_index(v, e)                                                      \\
  (long long)distance((v).begin(), lower_bound((v).begin(), (v).end(), e))
#define upper_index(v, e)                                                      \\
  (long long)distance((v).begin(), upper_bound((v).begin(), (v).end(), e))
long long mpow(long long a, long long n, long long mod = MOD) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
void pt() {
  cout << endl;
  return;
}
template <class Head> void pt(Head &&head) {
  cout << head;
  pt();
  return;
}
template <class Head, class... Tail> void pt(Head &&head, Tail &&...tail) {
  cout << head << " ";
  pt(forward<Tail>(tail)...);
}
void dpt() {
  if (!isDebugMode)
    return;
  cout << endl;
  return;
}
template <class Head> void dpt(Head &&head) {
  if (!isDebugMode)
    return;
  cout << head;
  pt();
  return;
}
template <class Head, class... Tail> void dpt(Head &&head, Tail &&...tail) {
  if (!isDebugMode)
    return;
  cout << head << " ";
  pt(forward<Tail>(tail)...);
}
template <class T> void enu(T v) {
  rep(i, v.size()) cout << v[i] << " ";
  cout << endl;
}
template <class T> void enu2(T v) {
  rep(i, v.size()) {
    rep(j, v[i].size()) cout << v[i][j] << " ";
    cout << endl;
  }
}
template <class T> void debug(T v) {
  if (!isDebugMode)
    return;
  rep(i, v.size()) cout << v[i] << " ";
  cout << endl;
}
template <class T> void debug2(T v) {
  if (!isDebugMode)
    return;
  rep(i, v.size()) {
    rep(j, v[i].size()) cout << v[i][j] << " ";
    cout << endl;
  }
}
template <class T1, class T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2> long long recgcd(T1 a, T2 b) {
  return a % b ? recgcd(b, a % b) : b;
}
bool valid(long long H, long long W, long long h, long long w) {
  return 0 <= h && h < H && 0 <= w && w < W;
}

void solve();

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  // cin >> testcase;
  while (testcase--)
    solve();
  return 0;
}
vector<long long> div_list(long long n) {
  vector<long long> list;
  for (long long i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      if (i == n / i) {
        list.emplace_back(i);
      } else {
        list.emplace_back(i);
        list.emplace_back(n / i);
      }
    }
  }
  sort(list.begin(), list.end());
  return list;
}

void solve() {
  ll N;
  cin >> N;
  ll ans = 0;
  for (ll c = 1; c <= N - 1; c++) {
    auto v = div_list(N - c);
    ans += v.size();
  }
  pt(ans);
}