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  ;
 }