数论：zoj 1951 || poj 2262 Goldbach's Conjecture

【转】http://blog.youkuaiyun.com/zxy_snow/article/details/6002626

 

 

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#define MAX 1000001
using namespace std;
int prime[MAX];
void Pri()
{
	for(int i=1; i<MAX; i++)
		prime[i] = 1;
	prime[0] = prime[1] = 0;
	for(int i=2; i<MAX/2; i++)
		for(int j=2; j*i<MAX; j++)
			prime[i*j] = 0;
}
int main(void)
{
	Pri();
	int n;
	while( scanf("%d",&n)  && n )
	{
		int flag = 1;
		for(int i=2; i<n/2+1; i++)
		{
			if( prime[i] && prime[n-i] )
			{
				printf("%d = %d + %d/n",n,i,n-i);
				flag = 0;
				break;
			}
		}
		if( flag )
			printf("Goldbach's conjecture is wrong./n");
	}
return 0;
}