zoj 1951 Goldbach's Conjecture

//就开始做这题的时候，竟然超时了，然后改为查表，亦超时，只好上网参考了别人的做法！#include "iostream"#include "cmath"using namespace std;int primer(int n){int i, k;k = sqrt(double(n));if (n == 1) return 0;for (i = 2; i <= k; i++){if (n % i == 0)return 0;}return 1;}int main(){int num, i;while (cin >> num && num){for (i = 3; i < num; i += 2){if (primer(i) && primer(num - i)){cout << num << " = " << i << " + " << num - i << endl;break;}}if (i == num)cout << "Goldbach's conjecture is wrong." << endl;}}