因为n<=2^31(往多了想最多就是二三十个数连续相乘),可以一个一个的找。
#include<iostream>
#include<stdio.h>
using namespace std;
bool IsPrime(long long int n)
{
if (n == 2 || n == 3)
return true;
else
{
for (long long int i = 2; i*i <= n; i++)
{
if (n%i == 0)
return false;
}
}
return true;
}
void find(long long int n,long long int &start,long long int &len)
{
long long int x, i, j;
for (i = 2; i <= n; i++)
{
x = i;
if (n%x == 0&&len==0&&start==-1)
start = i;
for (j = 1; j <= 31; j++)
{
x *= (i + j);
if (n%x==0)
{
if (j > len)
{
len = j;
start = i;
}
}
if (x > n)
break;
}
}
}
int main()
{
long long int n;
while (scanf("%lld",&n)!=EOF)
{
long long int start = -1, len = 0;
if (IsPrime(n))
printf("1\n%lld\n", n);
else
{
find(n,start,len);
printf("%lld\n", len + 1);
for (long long int i = 0; i <= len; i++)
{
printf("%lld%c", start + i, len - i ? '*' : '\n');
}
}
}
return 0;
}