一个研究课题 A Research Problem UVA10837

#include<cstring>
#include<algorithm>
#include<iostream>
#include <map>
using namespace std;
const int M=1e5+5;
#define int long long
#define inf 1e9
 
 int tot,prime[M],vis[M];
 int vec[M],vsize;
 
 int ans =inf;
 void init(int top){
 	int i,j; 
	vis[1]=1;
 	
	for(i=2;i<=top;i++){
		if(vis[i])  continue;
		prime[++tot]=i;
		for(j=i*2;j<=top;j+=i) vis[j]=1; 
	} 
 }
 void shai(int x){
 	vsize=0;
 	for(int i=1;i<=tot&&(prime[i]-1)*(prime[i]-1)<=x;i++){
 		if(x%(prime[i]-1)==0) vec[++vsize]=prime[i];
 	}
 }
 bool chk(int x){
 	for(int i=1;i<=tot&&prime[i]*prime[i]<=x;i++){
 		if(x%prime[i]==0) return 0;
 	}
 	for(int i=1;i<=vsize;i++){
 		if(vis[i] && x==vec[i]) return 0 ;
 	}
 	return 1;
 }
 void dfs(int cnt,int num,int A){
 	if(cnt>vsize){
 		if(num==1) ans=min(ans,A);
 		else if(chk(num+1)){
 			A*=(num+1); ans=min(ans,A);
 		}
 		return ;
 	}
 	dfs(cnt+1,num,A);
 	if(num%(vec[cnt]-1)) return ;
 	
 	vis[cnt]=1;
 	dfs(cnt+1,num/=(vec[cnt]-1),A*=vec[cnt]) ;
 	
 	while(num%vec[cnt]==0){
 		num/=vec[cnt],A*=vec[cnt] ;
 		dfs(cnt+1,num,A) ;
 	}
 	vis[cnt]=0;
 }
signed main() {
	init(1e5); 
	int m,cas=0; 
	while(cin>>m,m){
		shai(m);
		memset(vis,0,sizeof vis);
		ans=inf; 
	//	cout<<"len: "<<vsize<<"\n\n";
		dfs(1,m,1);
		printf("Case %lld: %lld %lld\n",++cas,m,ans);
	}
}