单词数(hdu2072字典树)

题意：找有多少种不同的单词

思路：字典树

每次插入一个单词都应find函数查找一遍，看是否存在，如果不存在sum++最后输出sum即可

#include
#include
#include
using namespace std;

struct Trie
{
    bool flag;
    struct Trie * child[26];
}Tri[8000000];
int alloc = 0;

struct Trie* creat_node()
{
    Trie* p;
    p = &Tri[alloc++];
    int i;    
    p -> flag = false;
    for(i = 0; i < 26; i++)
        p -> child[i] = NULL;
    return p;
}

void insert(Trie **p,char *str)
{
    int i,len;
    len = strlen(str);
    Trie *q;
    q = *p;
    for(i = 0; i < len; i++)
    {
        if(q -> child[str[i]-'a'] != NULL)
        {
            q = q -> child[str[i]-'a'];
        }
        else
        {
            q -> child[str[i]-'a'] = creat_node();
            q = q -> child[str[i]-'a'];
        }
    }
    q -> flag = true;
}

bool find(Trie **q,char *str)
{
    int i,len;
    len = strlen(str);
    struct Trie *p;
    p = *q;
    for(i = 0; i < len; i++)
    {
        if(p -> child[str[i]-'a'] != NULL)
        {
            p = p -> child[str[i]-'a'];
        }
        else
        {
            return false;
        }
    }
    if(p ->flag == true)
        return true;
    else
        return false;
}

int main()
{
    char c[10000];
            
    int sum = 0;
    while(gets(c) != NULL && c[0] != '#')
    {

        int i;
        alloc = 0,sum = 0;
        char s[1000];
        Trie * root;
        root = creat_node();
        char * tokstr = strtok(c," ");
        while(tokstr != NULL)
        {
            sscanf(tokstr,"%s",s);
            if(!find(&root,s))
            {
                sum++;insert(&root,s);
            }
            tokstr = strtok(NULL," ");
        }
        printf("%d\n",sum);
    
    }
    return 0;
}