HDU_1247 Hat’s Words(Trie 树)

　　Trie水题，将每个单词插入Trie树，然后暴力拆分每个单词到树中查找匹配即可！有几个要注意的细节，代码注释中都标上了。

My Code:

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;
const int MAX = 50007;
struct node
{
    int flag;
    node * next[26];
};

char dis[MAX][30];

node * newnode()
{
    int i;
    node * p = new node;
    p->flag = 0;
    for(i = 0; i < 26; i++)
        p->next[i] = NULL;
    return p;
}

void insert(node * root, char *s)
{
    node * p = root;
    int i, len = strlen(s), t;
    for(i = 0; i < len; i++)
    {
        t = s[i] - 'a';
        if(p->next[t] == NULL)
            p->next[t] = newnode();
        p = p->next[t];
    }
    p->flag = 1;

}

int search(node * root, char *s)
{
    node * p = root;
    int i, t, len = strlen(s);
    for(i = 0; i < len; i++)
    {
        t = s[i] - 'a';
        if(p->next[t] == NULL)
            return 0;
        p = p->next[t];
    }
    if(p->flag)
        return 1;
    return 0;
}

int main()
{
    //freopen("data.in", "r", stdin);
    int n = 0, i, j, k;
    char s1[30], s2[30];
    node * root = newnode();
    while(scanf("%s", dis[n]) != EOF)
    {
        insert(root, dis[n]);
        n++;
    }
    for(i = 0; i < n; i++)   //拆分
    {
        int len = strlen(dis[i]);
        memset(s1, 0, sizeof(s1));    //每次置空字符串数组，否则会段错误（这里就是数组溢出）
        for(j = 0; j < len-1; j++)
        {
            s1[j] = dis[i][j];
            memset(s2, 0, sizeof(s2));    //同理
            for(k = j+1; k < len; k++)
            {
                s2[k-j-1] = dis[i][k];
            }
            if(search(root, s1) && search(root, s2))
            {
                puts(dis[i]);
                break;
            }
        }

    }
    return 0;
}