HDU 1251 统计难题(字典树)

                                     统计难题

                                                  Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 131070/65535 K (Java/Others)

                                                                       Total Submission(s): 12855    Accepted Submission(s): 5433

Problem Description

Ignatius最近遇到一个难题,老师交给他很多单词(只有小写字母组成,不会有重复的单词出现),现在老师要他统计出以某个字符串为前缀的单词数量(单词本身也是自己的前缀).

 

Input

输入数据的第一部分是一张单词表,每行一个单词,单词的长度不超过10,它们代表的是老师交给Ignatius统计的单词,一个空行代表单词表的结束.第二部分是一连串的提问,每行一个提问,每个提问都是一个字符串.
注意:本题只有一组测试数据,处理到文件结束.

 

Output

对于每个提问,给出以该字符串为前缀的单词的数量.

 

Sample Input

banana

band

bee

absolute

acm

 

ba

b

band

abc

 

Sample Output

2

3

1

0

 

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1251

 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct _TrieTree
{
    int  count;
    bool flag;
    struct _TrieTree *next[26];

}TrieNode;

TrieNode *CreateTrieTree()   //创建字典树
{
    TrieNode *node = (TrieNode *)malloc(sizeof(TrieNode));
    node->count = 0;
    node->flag = false;
    for(int i = 0; i < 26; i++)
        node->next[i] = NULL;

    return node;
}

void InsertTrieTree(TrieNode *root, char word[]) //插入字符串
{
    TrieNode *p = root;
    int length = strlen(word);
    for(int i = 0; i < length; i++)
    {
        int index = word[i] - 97;
        if(p->next[index] == NULL)
        {
            p->next[index] = CreateTrieTree();
        }
        p = p->next[index];
        p->count++;
    }
    p->flag = true;
}

int QueryTrieTree(TrieNode *root, char word[])   //查询字符串
{
    TrieNode *p = root;
    int length = strlen(word);
    for(int i = 0; i < length; i++)
    {
        int index = word[i] - 97;
        if(p->next[index] == NULL)
            return 0;

        p = p->next[index];
    }

    return p->count;
}

int main(int argc, char* argv[])
{
    const int WORD_LEN = 15;
    char word[WORD_LEN];

    TrieNode *root = CreateTrieTree();

    while(gets(word))
    {
        if(strlen(word) == 0)
            break;
        
        InsertTrieTree(root, word);
    }

    while(scanf("%s", word) != EOF)
    {
        int cnt = QueryTrieTree(root, word);

        printf("%d\n", cnt);
    }

    return 0;
}