1096. Consecutive Factors (20)

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本文介绍了一种算法，用于找出正整数N的最大连续因子序列，并列出这些因子。输入为一个正整数N，输出包括最大连续因子的数量及具体的连续因子序列。

Among all the factors of a positive integer N, there may exist several consecutive numbers. For example, 630 can be factored as 3*5*6*7, where 5, 6, and 7 are the three consecutive numbers. Now given any positive N, you are supposed to find the maximum number of consecutive factors, and list the smallest sequence of the consecutive factors.

Input Specification:

Each input file contains one test case, which gives the integer N (1<N<2³¹).

Output Specification:

For each test case, print in the first line the maximum number of consecutive factors. Then in the second line, print the smallest sequence of the consecutive factors in the format "factor[1]*factor[2]*...*factor[k]", where the factors are listed in increasing order, and 1 is NOT included.

Sample Input:

Sample Output:

3
5*6*7
代码实现
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;

int main()
{
    long long n;
    cin>>n;
    long long sqr=sqrt(1.0*n),ansI=0,ansLen=0;
    for(long long i=2;i<=sqr;i++)
    {
        long long temp=1,j=i;
        while(1)
        {
            temp *=j;
            if(n%temp!=0) break;
            if(j-i+1>ansLen)
            {
                ansI=i;
                ansLen=j-i+1;
            }
            j++;
        }
    }
    if(ansLen==0)
    {
        printf("1\n%lld",n);
    }
    else
    {
        printf("%lld\n",ansLen);
        for(long long i=0;i<ansLen;i++)
        {
            printf("%lld",ansI + i);
            if(i<ansLen-1)
            {
                printf("*");
            }
        }
    }
    return 0;
}