团体程序设计天梯赛 L1-006. 连续因子

Two ways:

1.接近O(n)

 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>

 int main()
 {
     long n,i,j,k,num=,b;
     scanf("%ld",&n);
     for (i=;i<=(long)sqrt(n);i++)
     {
         k=n;
         for (j=i;;j++)
             if (k%j==)
                 k=k/j;
             else
                 break;
         if (j-i>num)
         {
             num=j-i;
             b=i;
         }
     }
     if (num==)
     {
         num=;
         b=n;
     }
     printf("%ld\n",num);
     for (i=b;i<b+num;i++)
     {
         printf("%ld",i);
         if (i!=b+num-)
             printf("*");
     }
     return ;
 }

2.O(kn) 会超时

 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>

 int main()
 {
     long n,i,j,k,num=,b;
     scanf("%ld",&n);
     for (i=;i<=(long)sqrt(n);i++)
     {
         k=n;
         for (j=i;;j++)
             if (k%j==)
                 k=k/j;
             else
                 break;
         if (j-i>num)
         {
             num=j-i;
             b=i;
         }
     }
     if (num==)
     {
         num=;
         b=n;
     }
     printf("%ld\n",num);
     for (i=b;i<b+num;i++)
     {
         printf("%ld",i);
         if (i!=b+num-)
             printf("*");
     }
     return ;
 }

#include <stdio.h>#include <stdlib.h>#include <math.h>
int main(){long n,i,j,k,num=0,b;scanf("%ld",&n);for (i=2;i<=(long)sqrt(n);i++){k=n;for (j=i;;j++)if (k%j==0)k=k/j;elsebreak;if (j-i>num){num=j-i;b=i;}}if (num==0){num=1;b=n;}printf("%ld\n",num);for (i=b;i<b+num;i++){printf("%ld",i);if (i!=b+num-1)printf("*");}return 0;}