8.10 trie树模板

字典树是一种很简单的数据结构，就是将字符串存在书上，相同前缀进行压缩

模板题：http://acm.hdu.edu.cn/showproblem.php?pid=1251

#include<bits/stdc++.h>

#define fi first
#define se second
#define rep( i ,x ,y ) for( int i= x; i<= y ;i++ )
#define reb( i ,y ,x ) for( int i= y; i>= x ;i-- )
#define mem( a ,x ) memset( a ,x ,sizeof(a))
using namespace std;

const int maxn = 500000;
char s[100] ;
int trie[maxn][30] ,sum[maxn];
int tot = 0;

//更新
void updata( ){
     int len = strlen( s );
     int root = 0;
     for( int i = 0 ;i<len ;i++){
         int id = s[i] - 'a';
         if( !trie[root][id] )trie[root][id] = ++tot;
         root  = trie[root][id];
         sum[root]++;
     }
}

//查找
int find( ){
     int len = strlen( s );
     int root = 0;
     for( int i = 0; i < len ;i++ ){
         int x = s[i] - 'a';
         //cout<<s[i]<<endl;
         if( !trie[root][x] )return 0;
         root = trie[root][x];
        // cout<<root<<endl;
     }
     return sum[root];
}
int main( ){
    mem( trie , 0 );
    mem( sum ,0 );

     while( 1 ){
         gets( s );
         if( s[0] == '\0' )break;
         updata( );
     }

     while( ~scanf("%s" ,&s) ){
         printf("%d\n" ,find( ) );
     }
     return 0;
}