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素数筛法+二分可以过#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
#define MAXN 1000010
#define ll long long
int n;
int Prime[MAXN];
bool NotPrime[MAXN];
int pcnt;
void InitPrime(int n)
{
for(ll i=2;i<=n;i++)
{
if(!NotPrime[i])
{
Prime[pcnt++]=i;
for(ll j=i*i;j<=n;j+=i) NotPrime[j]=true;
}
}
}
int main()
{
InitPrime(999999);
while(scanf("%d",&n),n)
{
for(int i=0;i<pcnt;i++)
{
int a=Prime[i];
int b=*lower_bound(Prime,Prime+pcnt,n-a);
if(a+b==n)
{
printf("%d = %d + %d\n",n,a,b);
break;
}
}
}
return 0;
}
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