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  1. //473
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4. typedef long long ll;
  5. ll L , R;
  6.  
  7. ll get(ll n){
  8.     if(n == 0) return 0;
  9.     ll s = sqrt(n), ans = 0;
  10.     for(int i = 1; i <= n / s; i++) ans += (n / i); 
  11.  
  12.     // for(int i = 1; i < s; i++){
  13.     //     ll r = n / i; 
  14.     //     ll l = n / (i + 1) + 1;
  15.     //     ans += i * (r - l + 1);
  16.     // }
  17.  
  18.     for(int i = 2; i <= s; i++){
  19.         ll l = n / i, r = n / (i - 1);
  20.         ans += (i - 1) * (r - l);
  21.     }
  22.  
  23.     return ans;
  24. }
  25.  
  26. int main(){
  27.     ios_base::sync_with_stdio(0);
  28.     cout.tie(0);
  29.     cin.tie(0);
  30.     freopen("tongsouoc.inp", "r", stdin); freopen("tongsouoc.out", "w", stdout);
  31.     cin >> L >> R;
  32.     cout << get(R) - get(L - 1);
  33.  
  34.  
  35. }
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/zdIuSu
language:
C++14 (gcc 8.3)
created:
280 days ago
visibility:
public

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