Q686: Goldbach's Conjecture(II)
//Q686 Goldbach's Conjecture(II) //Accepted 2008-04-21 13:35:20 #include <iostream> #include <cmath> using namespace std; int main(void) { int n = 0, nt; while(cin >> n) { if (n == 0) break; int ct = 0, count = 0; nt = n; int *prime = new int [n]; //get prime for(int i = 2; i <= nt; i++) { bool isprime = true; for(int j = 2; j <= sqrt(i) && isprime; j++) isprime = i % j != 0; if (isprime) prime[ct++] = i; } for(int i = 0; i < ct; i++) { int becheck = n - prime[i]; for(int j = 0; j < ct; j++) if (becheck == prime[j] && prime[i] >= prime[j]) { count++; break; } } cout << count << endl; ...