HDU 2594 最长相同前后缀

Sample Input
clinton
homer
riemann
marjorie

Sample Output
0
rie 3

输入两个字符串 ，求最长相同前后缀
直接把两个字符串连接在一起求next就行了，唯一要注意的就是长度不能大于原来任一字符串的长度，如果长度大于了，要选择len1和len2中较小的一个输出。

 # include <cstdio>

 # include <cstring>

 using namespace std ;

 char s1[] ;

 char s2[] ;

 char s3[] ;

 int next[] ;

 int len1 , len2;

 void getNext()

 {

     int j, k;

     j = ; k = -; next[] = -;

     while(j < len1+len2)

         if(k == - || s1[j] == s1[k])

             next[++j] = ++k;

         else

             k = next[k];

 }

 int main ()

 {

     while (scanf("%s%s" , &s1 , &s2) != EOF)

     {

         len1 = strlen(s1) ;

         len2 = strlen(s2) ;

         strcat(s1 , s2) ;

         getNext() ;

         int i ;

         for (i =  ; i < next[len1 + len2] ; i++)

         {

             s3[i] = s1[i] ;

         }

         s3[i] = '\0' ;

         if (next[len1 + len2])

         {

             if (next[len1 + len2] > len1 ||next[len1 + len2] > len2)

             {

                 if (len1 > len2)

                     printf("%s %d\n" ,s2 ,len2) ;

                 else

                     {

                         s3[len1] = '\0' ;

                         printf("%s %d\n" ,s3 ,len1) ;

                     }

             }

             else

               printf("%s %d\n" ,s3 ,next[len1 + len2]) ;

         }

         else

            printf("0\n") ;

     }

     return  ;

 }