poj 2503 Trie树

　　典型的Trie树， 算是复习一下字符串吧， 就是输入有点恶心，代码如下：

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
const int maxn = 500000+100;
struct Trie{
    bool isword;
    int next[26];
    char words[15];
    Trie(){
        memset(next, -1, sizeof(next));
        isword = false;
    }
}Root;
Trie node[maxn];
int n;

void Insert(char *tar){
    Trie *head = &Root;
    char *s = tar;
    while(*tar!=' ') tar++;
    *tar='';
    tar++;
    while(*tar!=''){
        int id = *tar - 'a';
        if(head->next[id] == -1){
            head->next[id] = n++;
        }
        head = &node[head->next[id]];
        tar++;
    }
    head->isword = true;
    //printf("s = %s
", s);
    strcpy(head->words, s);
}

char *Search(char *tar)
{
    Trie *head = &Root;
    while(*tar){
        int id = *tar - 'a';
        if(head->next[id] == -1) return NULL;
        head = &node[head->next[id]];
        tar++;
    }
    if(head->isword) return head->words;
    else return NULL;
}

char str[100];

int main(){
    n = 0;
    while(gets(str)){
        bool kongge = false;
        int len = strlen(str);
        for(int i=0; i<len; i++) {
            if(str[i] == ' '){
                    kongge = true;
                    break;
            }
        }
        if(str[0]<'a'||str[0]>'z') continue;
        if(kongge) Insert(str);
        else {
            char *p = Search(str);
            if(p == NULL) printf("eh
");
            else printf("%s
", p);
        }
    }
    return 0;
}