HDU 1251 字典树

题意：中文题。。。问你某个单词是多少单词的前缀

思路：很裸的字典树。。。人生第一次用。。。

#include <cstdio>
#include <cstring>
using namespace std;

#define REP( i, a, b ) for( int i = a; i < b; i++ )

struct Trie{
          int va;
          Trie *next[26];
          Trie(int va) : va(va) { REP(i, 0, 26) next[i] = NULL; }
};

void CreatTrie(Trie *root, char *str){
          Trie *p = root;
          int len = strlen(str);
          REP(i, 0, len){
                    int id = str[i] - 'a';
                    if(p -> next[id] == NULL){
                              Trie *q = new Trie(1);
                              p -> next[id] = q;
                              p = p -> next[id];
                    }
                    else{
                              p -> next[id] -> va++;
                              p = p -> next[id];
                    }
          }
}

int FindTrie(Trie *root, char *str){
          Trie *p = root;
          int len = strlen(str);
          REP(i, 0, len){
                    int id = str[i] - 'a';
                    if(p -> next[id] == NULL) return 0;
                    p = p -> next[id];
          }
          return p -> va;
}

int main()
{
          //freopen("in.txt", "r", stdin);
          char str[15];
          Trie *root = new Trie(0);
          while(gets(str) && strcmp(str, "\0")) CreatTrie(root, str);
          while(~scanf("%s", str)) printf("%d\n", FindTrie(root, str));
          return 0;
}