字典树

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct T {
    T * ch[26];  
    int n, flag;
}rt;
char in[15];
void init ( T * t ) {
     for ( int i = 0; i < 26; ++ i ) t->ch[i] = NULL;    
     t->n = t->flag = 0;
}
void insert ( T *t, char *in ) {
     if ( *in ) {
         if ( t->ch[ *in - 'a' ] == NULL ) {
            t->ch[ *in - 'a' ] = ( T * ) malloc ( sizeof ( T ) );
            init ( t->ch[ *in - 'a' ] );    
         }    
         t->ch[ *in - 'a' ]->n ++;
         insert ( t->ch[ *in - 'a' ], in + 1 );
     } else {
         t->flag = 1;     
     }   
}

int find ( T *t, char *in ) {
    if ( t->ch[ *in - 'a' ] != NULL ) {
        if ( *( in + 1 ) == '\0' ) {
            return t->ch[ *in - 'a' ]->n;    
        }
        return find ( t->ch[ *in - 'a' ], in + 1 );
    } else return 0;   
}
int main ()
{
    while ( gets ( in ) ) {
          if ( strlen ( in ) == 0 ) break;
          insert ( &rt, in );     
    }
    while ( ~scanf ( "%s", in ) ) {
          printf ( "%d\n", find ( &rt, in ) );     
    }
    return 0;   
}