《 字典树模板_递归 》

 1 #include <iostream>
 2 #include <cstdlib>
 3 #include <cstdio>
 4
 5
 6 using namespace std;
 7
 8 struct tree
 9 {
10     int val;
11     tree *next[26];
12 };
13 tree *head;
14
15 void Insert(tree *p, char *ch, int pp)
16 {
17     if (ch[pp] == ‘\0‘)
18     {
19         p->val++;
20         return;
21     }
22     if (p->next[ch[pp] - ‘a‘] == NULL)
23     {
24         tree *q = (tree *)malloc(sizeof(tree));
25         q->val = 0;
26         for (int i = 0; i < 26; i++)
27         {
28
29             q->next[i] = NULL;
30         }
31         p->next[ch[pp] - ‘a‘] = q;
32
33     }
34     Insert(p->next[ch[pp] - ‘a‘], ch, pp+1);
35 }
36
37 int Query(tree *p, char *ch, int pp)
38 {
39     if(ch[pp] == ‘\0‘)
40         return p->val;
41     if(p->next[ch[pp] - ‘a‘] == NULL)
42         return 0;
43     else
44         Query(p->next[ch[pp] - ‘a‘], ch, pp+1);
45 }
46
47 int Query(char *ch)
48 {
49     return Query(head, ch, 0);
50 }
51
52
53 int main()
54 {
55
56     char a[250], b[250];
57     while(scanf("%s%s",a,b) != EOF)
58     {
59         head = (tree *)malloc(sizeof(tree));
60         head->val = 0;
61         for(int i = 0; i < 26; i++)
62         {
63             head->next[i] = NULL;
64         }
65         Insert(head,a,0);
66         cout<<Query(b)<<endl;
67     }
68
69 }