NK1053 哥德巴赫猜想

//Description: NKUOJ 1053 哥德巴赫猜想//Date: 2011/06/21//Author: Frank#include <iostream>#include <cstdio>#include <cmath>#include <vector>#include <cstdio>using namespace std;vector<int> vPrime;bool IsPrime(int n){int i = 0;for(i=2;i<=sqrt(n);i++)if(n % i == 0 && n!=2)return false;return true;}void InitPrime(){int i=2;int iMax = 1024*32;for(i=2; i<=iMax; i++)if(IsPrime(i))vPrime.push_back(i);}int main(){int n = 0;int i = 0;int j = 0;int iCount = 0;InitPrime();while(scanf("%d",&n) && n){iCount = 0;i = 0;j = vPrime.size() - 1;while(i<=j){if(vPrime[i] + vPrime[j] < n)i++;else if(vPrime[i] + vPrime[j] > n)j--;else if(vPrime[i] + vPrime[j] == n){i++;iCount++;}}printf("%d/n",iCount);}return 0;}