题目链接:https://uva.onlinejudge.org/index.php?option=onlinejudge&page=show_problem&problem=1732
hint:素因子分解
#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
typedef long long LL;
int main()
{
int m,ss,flag,cnt;
int cas=1;
while(scanf("%d",&m),m)
{
LL ans=0;
ss=(int)sqrt((double)m+0.5);//不要ss=吗;
flag=0;
for(int i=2; i<=ss; i++)//注意这里千万不要i*i<=ss啊!!!
{
if(m % i == 0)
{
flag++;
cnt=1;
while(m % i == 0)
{
cnt*=i;
m/=i;
}
ans+=cnt;
}
}
if(flag == 0)
ans=(LL)m+1;
else if(m>1 || flag == 1)
ans+=m;
printf("Case %d: %lld\n",cas++,ans);
}
return 0;
}