//那个单词是有出现的两个单词构成的
# include <cstdio>
# include <cstring>
# include <algorithm>
# include <iostream>
# define MAX 26
using namespace std;
typedef struct Trie_Node
{
    bool isWord;
    struct Trie_Node *next[MAX];
} Trie;
char s[50000][50];
void insert(Trie *root,char *word)//生成字典树
{
    Trie *p=root;
    while(*word!='\0')
    {
        if(p->next[*word-'a']==NULL)
        {
            Trie *temp=(Trie*)malloc(sizeof(Trie));
            for(int i=0; i<MAX; i++)
            {
                temp->next[i]=NULL;
            }
            temp->isWord=false;
            p->next[*word-'a']=temp;
        }
        p=p->next[*word-'a'];
        word++;
    }
    p->isWord=true;
}
bool search(Trie *root,char *word)//查找单词是否存在
{
    Trie *p=root;
    for(int i=0; word[i]!='\0'; i++)
    {
        if(p==NULL||p->next[word[i]-'a']==NULL)
            return false;
        p=p->next[word[i]-'a'];
    }
    return p->isWord;
}
void del(Trie *root)//释放空间
{
    for(int i=0; i<MAX; i++)
    {
        if(root->next[i]!=NULL)
        {
            del(root->next[i]);
        }
    }
    free(root);//释放malloc申请的空间
}
int main()
{
    int i,j;
    int count=0;
    char str[50];
    Trie *root=(Trie*)malloc(sizeof(Trie));
    for(i=0; i<MAX; i++)
    {
        root->next[i]=NULL;
    }
    root->isWord=false;
    while(~scanf("%s",str))
    {
        strcpy(s[count++],str);
        insert(root,str);
    }
    for(i=0; i<count; i++)
    {
        for(j=1; j<=strlen(s[i])-1; j++)
        {
            char temp1[50]= {'\0'};
            char temp2[50]= {'\0'};
            strncpy(temp1,s[i],j);//枚举两部分
            strncpy(temp2,s[i]+j,strlen(s[i])-j);
            if(search(root,temp1)&&search(root,temp2))
            {
                printf("%s\n",s[i]);
                break;
            }
        }
    }
    del(root);
    return 0;
}

hdu 1247 Hat’s Words (字典树模板)