PAT|1096. Consecutive Factors

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;
}