解题报告-HDOJ-1075（字典树）

这一题和1251都是字典树，题意是给出单词以及单词的翻译，最后让你用这些单词翻译给出来的语句。

我的思路是，在每一个flag为true的单词保存对应的翻译，当翻译句子时，搜索字典树，当找到该单词、flag为true、并且该单词已经结束（很重要），就输出对应的翻译，否则，输出原来的单词。

以下是实现代码：

#include <iostream>

using namespace std;

char str[3000 + 50]; 

typedef struct Node 
{
    Node *child[26];
    int n;
    bool flag;
    char str[15];
}Node;

void Insert (Node *root, char *str,char *ch)
{
    int len = strlen (str);
    Node *ans = root;
    for (int i =0; i < len; i ++)
    {
        if (ans->child[str[i] - 'a'] == NULL)
        {
            Node *NewNode = (Node *) malloc (sizeof (Node));    
            NewNode->n = 1;
            NewNode->flag = false;
            for (int j = 0; j < 26; j++)
            {
                NewNode->child[j] = NULL;
            }
            ans->child[str[i] - 'a'] = NewNode;
            ans = NewNode;
        }
        else
        {
            ans = ans->child[str[i] - 'a'];
            ans->n ++;
        }
    }
    ans->flag = true;
    strcpy (ans->str,ch);
}

bool Search (Node *root, char *str,char *ch)
{
    int len = strlen (str);
    Node *ans = root;
    int i;
    for (i = 0; i < len; i ++)
    {
        if (ans->child[str[i] - 'a'] != NULL)
        {
            ans = ans->child[str[i] - 'a'];
        }
        else
        {
            break;
        }
    }
    if (ans->flag == true && i == len)//i==len这个条件不能少
    {
        strcpy (ch, ans->str);
        return true;
    }
    return false;
}

int main ()
{
    Node *root = (Node *)malloc (sizeof (Node));
    for (int i = 0; i < 26; i ++)
    {
        root->child[i] = NULL;
    }
    root->n = 0;
    
    char ch1[15],ch2[15];
    while (1)
    {
        scanf ("%s",ch1);
        if (strcmp (ch1, "START") == 0)
        {
            continue;
        }
        else if (strcmp (ch1, "END") == 0)
        {
            break;
        }

        scanf("%s",ch2);
        Insert (root, ch2, ch1);
    }

    getchar();
    while (1)
    {
        gets (str);
        if (strcmp (str, "START") == 0)
        {
            continue;
        }
        else if (strcmp (str, "END") == 0)
        {
            break;
        }

        char ch3[15];
        
        int cnt = 0;
        for (int i = 0; i < strlen (str); i++)
        {
            if (!(str[i] >= 'a' && str[i] <= 'z'))
            {
                ch3[cnt] = 0;
                cnt = 0;
                char rech[15];
                if (Search (root, ch3, rech))
                {
                    cout<<rech<<str[i];
                }
                else
                {
                    cout<<ch3<<str[i];
                }
            }
            else
            {
                ch3[cnt ++] = str[i];
            }
        }
        cout<<endl;
    }
}
/*
START
from fiwo
hello difh
mars riwosf
earth fnnvk
like fiiwj
END
START
difhi, i'm fiwo riwosf.
i fiiwj fnnvk!
END
*/