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  1. #include <iostream>
  2. #include <vector>
  3. #include <unordered_map>
  4. #include <cmath>
  5. using namespace std;
  6.  
  7. bool prime (int x){ //функция для проверки простоты нечётного числа
  8. 	bool pr=true;
  9. 	for(int i=2; i<=sqrt(x);i++)if(!(x%i))pr=false;
  10. 	return pr;
  11. }
  12. int main() {
  13. 	vector <int> v,prime_v;
  14. 	unordered_map <int,bool> prime_m;
  15. 	int u,i,j,maxx=0;
  16. 	while(cin>>u){
  17. 		v.push_back(u);
  18. 		maxx=max(maxx,u);//максимальное значение во входном потоке
  19. 	}
  20. 	for(i=3;i<=maxx;i+=2){
  21. 		if(prime(i)){
  22. 			prime_m[i]=true;
  23. 			prime_v.push_back(i); 
  24. 		}
  25. 	}
  26. 	int *dp,k;
  27. 	dp = new int [maxx+1];
  28. 	for(i=0;i<=maxx;i++)dp[i]=0;
  29. 	for(i=8;i<=maxx;i++){//динамика
  30. 		if(i%2){
  31. 			for(j=0;(j<prime_v.size())&&(prime_v[j]<i);j++){
  32. 				k=i-prime_v[j];
  33. 				if(dp[k]){
  34. 					dp[i]+=dp[k];
  35. 					if((prime_m[k-prime_v[j]])&&((k-prime_v[j])!=prime_v[j]))--dp[i];
  36. 				}
  37. 			}
  38. 		}
  39. 		else{
  40. 			for(j=0;(j<prime_v.size())&&(prime_v[j]<(i/2));j++){
  41. 				k=i-prime_v[j];
  42. 				if(prime_m[k])dp[i]++;
  43. 			}
  44. 		}
  45. 		if(i%2)dp[i]/=3;
  46. 	}
  47. 	for(i=0;i<v.size();i++)cout<<dp[v[i]]<<'\n';
  48. 	return 0;
  49. }
Success #stdin #stdout 0.42s 15872KB
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https://ideone.com/JpflS1
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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