题目：你到了新的国家，手中有一个字典，把对应的语言翻译成英语。

分析：字符串，字典树。利用新语言建树，对应节点存储相应的英文单词，查询输出。

说明：强大的ungetc函数。

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

using namespace std;

char Nword[21],Eword[21];

/* Trie define */  
#define nodesize 1000001    //节点个数   
#define dictsize 26         //字符集大小   

typedef struct node 
{  
    int   flag;            //值域   
    node* next[dictsize];  
    char  words[21];
}tnode;  
tnode  dict[nodesize];  
int    ID[256];  

class Trie  
{  
    private:  
        int    size;  
        int    count;
        tnode* root;  
    public:  
        Trie() {makeID(); initial();}  
        void makeID() { 
            for ( int i = 0 ; i < 26 ; ++ i )  
                ID['a'+i] = i;
        }  
        void initial() {  
            memset(dict, 0, sizeof(dict)); 
            count=0;size=0;root=newnode();  
        }  
        tnode* newnode() {return &dict[size ++];}  
        void insert(char* word, char *text) {  
            tnode* now = root;  
            for (int i = 0 ; word[i] ; ++ i) {
                if (!now->next[ID[word[i]]])  
                    now->next[ID[word[i]]] = newnode();  
                now = now->next[ID[word[i]]];  
            }
			now->flag = 1;
            strcpy(now->words, text);
        }  
        void query(char* word) {
            tnode* now = root;
            for (int i = 0 ; word[i] ; ++ i) {
                if (!now->next[ID[word[i]]]) {
					printf("eh\n");
					return;
				}  
                now = now->next[ID[word[i]]];  
            }
			printf("%s\n",now->words);
        }
}trie;  
/* Trie  end */  

int main()
{
	trie.initial();
	char buf;
	while ((buf = getchar()) != '\n') {
		ungetc(buf,stdin);
		scanf("%s %s",Eword,Nword);
		trie.insert(Nword,Eword);
		getchar();
	}
	
	while (~scanf("%s",Nword)) 
		trie.query(Nword);
	
	return 0;
}

UVa 10282 - Babelfish