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


// Problem : C - A x B + C
// Contest : AtCoder - AtCoder Beginner Contest 179
// URL : https://atcoder.jp/contests/abc179/tasks/abc179_c
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define int long long
#define db double
#define mod 1000000007
#define pb push_back
#define pp pair<int, int>
#define rep(i, a, b) for (int i = a; i < b; i++)
#define repe(i, a, b) for (int i = a; i <= b; i++)
#define repr(i, a, b) for (int i = b; i >= a; i--)
#define maxn 1000005
#define ss second
#define ff first
#define all(a) a.begin(), a.end()
#define lb lower_bound
#define ub upper_bound
#define ordered_set                                                            \\
  tree<int, null_type, less<int>, rb_tree_tag,                                 \\
       tree_order_statistics_node_update>
int inv(int a, int b) { return 1 < a ? b - inv(b % a, a) * b / a : 1; }
int spf[maxn];
void solve() {
  int n, ans = 1;
  cin >> n;
  for (int i = 1; i <= n; i++)
    spf[i] = i;
  for (int i = 2; i <= n; i++)
    if (spf[i] == i)
      for (int j = i; j <= n; j += i)
        if (spf[j] == j)
          spf[j] = i;
  for (int i = 2; i < n; i++) {
    unordered_map<int, int> mp;
    int j = i;
    while (j > 1) {
      mp[spf[j]]++;
      j /= spf[j];
    }
    int tmp = 1;
    for (auto [a, b] : mp)
      tmp *= (b + 1);
    ans += tmp;
  }
  cout << ans;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  // cin >> t;
  while (t--)
    solve();
  return 0;
}


Error: TLE

Fixed submission:


// Problem : C - A x B + C
// Contest : AtCoder - AtCoder Beginner Contest 179
// URL : https://atcoder.jp/contests/abc179/tasks/abc179_c
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define int long long
#define db double
#define mod 1000000007
#define pb push_back
#define pp pair<int, int>
#define rep(i, a, b) for (int i = a; i < b; i++)
#define repe(i, a, b) for (int i = a; i <= b; i++)
#define repr(i, a, b) for (int i = b; i >= a; i--)
#define maxn 200005
#define ss second
#define ff first
#define all(a) a.begin(), a.end()
#define lb lower_bound
#define ub upper_bound
#define ordered_set                                                            \\
  tree<int, null_type, less<int>, rb_tree_tag,                                 \\
       tree_order_statistics_node_update>
int inv(int a, int b) { return 1 < a ? b - inv(b % a, a) * b / a : 1; }
void solve() {
  int n, ans = 0;
  cin >> n;
  for (int i = 1; i < n; i++) {
    for (int j = 1; j <= sqrt(i); j++) {
      if (i % j == 0)
        ans += 2;
      if (j == sqrt(i))
        ans--;
    }
  }
  cout << ans;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  // cin >> t;
  while (t--)
    solve();
  return 0;
}