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  1.  
  2. #include <iostream>
  3. #include <bits/stdc++.h>
  4. using namespace std;
  5. int ssprime(int num){
  6.     int size=((num-2)/2)+1,i;
  7.     bool arr[size];
  8.     memset(arr,false,sizeof(size));
  9.     for(i=1;i<size;i++){
  10.         for(int j=i;(i+j+(2*i*j))<=size;j++){
  11.             arr[i+j+(2*i*j)]=true;
  12.         }
  13.     }
  14.     int sum=0;
  15.     if(num>=5){
  16.         sum=2;
  17.     for(i=1;i<size;i++){
  18.         if(arr[i]==false && sum< num){
  19.             sum+=(2*i)+1;
  20.         }
  21.         if(sum==num)
  22.         break;
  23.     }
  24.     }
  25.     else
  26.     return 0;
  27.     if (sum==num)
  28.     return 1;
  29.     return 0;
  30. }
  31. bool is_prime(int n)
  32.     {
  33.          int i,sq,count=0;
  34.          if(n==1)
  35.            return false;
  36.          if(n==2)
  37.            return true;
  38.          if(n%2==0)
  39.            return false;
  40.          sq=sqrt(n);
  41.          for(i=2;i<=sq;i++)
  42.          {
  43.             if(n%i==0)
  44.               return false;  
  45.          }
  46.           return true;
  47. }
  48. int main()
  49. {
  50.     int num,count=0;
  51.     cin>>num;
  52.     for (int i=2;i<=num;i++){
  53.         if(is_prime(i))
  54.         count+=ssprime(i);
  55.     }
  56.     cout<<count;
  57.     return 0;
  58. }
Success #stdin #stdout 0s 15240KB
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https://ideone.com/2xVrFo
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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