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leminhkt

noname59

Jun 15th, 2020
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C++ 0.48 KB | None | 0 0
  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4.  
  5. const int MAX = 5000000;
  6. int a[MAX + 1];
  7. void eratosthenes(){
  8.     a[1] = -1;
  9.     for(int i = 2; i*i <= MAX; i++){
  10.         a[i*i] += i;
  11.         for(int j = i*i + i; j <= MAX; j += i)
  12.             a[j] += i + (j/i);
  13.     }
  14. }
  15. int sum(int x){return a[x] + x + 1;}
  16.  
  17.  
  18. int n, x, res;
  19.  
  20.  
  21. int main(){
  22.     eratosthenes();
  23.     cin >> n;
  24.     while(n--){
  25.         cin >> x;
  26.         res += (sum(x) < 2*x);
  27.     }
  28.     cout << res;
  29. }
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