LightOJ1035 Intelligent Factorial Factorization（算数基本定理）

#include <bits/stdc++.h>
using namespace std;
const int maxn=100+5;
bool visit[maxn];
int prime[maxn],e[maxn],n;
void prime_table(){
memset(visit,true,sizeof(visit));
memset(prime,0,sizeof(prime));
int num=0;
for(int i=2;i<=maxn;++i){
if (visit[i]==true){
num++;
prime[num]=i;
}
for (int j=1;((j<=num)&&(i*prime[j]<=maxn));++j){
visit[i*prime[j]]=false;
if (i%prime[j] == 0)
break;
}
}
}
void getfactor(int n){
for(int i=2;i<=n;i++){
int tmp=n;
if(visit[i]==true)
while(tmp%i==0){
e[i]++;
tmp/=i;
}
}
}
int main(){
//freopen("input.txt","r",stdin);
prime_table();
int T,cnt=0;
scanf("%d",&T);
while(T--){
memset(e,0,sizeof(e));
scanf("%d",&n);
for(int i=2;i<=n;i++){
getfactor(i);
}
printf("Case %d: %d =",++cnt,n);
int k;
for(int i=2;i<=n;i++)
if(e[i]!=0){
printf(" %d (%d)",i,e[i]);
k=i;
break;
}
for(int i=k+1;i<=n;i++)
if(e[i]!=0){
printf(" * %d (%d)",i,e[i]);
}
cout<<endl;
}
}