SDUT 2137 数据结构实验之求二叉树后序遍历和层次遍历

 题目链接：http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2137

  后序遍历没啥好说的，递归就好，层次遍历有点BFS的感觉。

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <stdlib.h>
 4 struct tree
 5 {
 6     char l;
 7     struct tree *left,*right;
 8 };
 9 struct tree *build(char *p,char *s,int n)
10 {
11     struct tree *tail;
12     int i;
13     if(n <= 0)return NULL;
14     tail = (struct tree *)malloc(sizeof(struct tree));
15     for(i = 0;i <= n-1;i ++)
16     {
17         if(p[0] == s[i])
18         break;
19     }
20     tail ->l = p[0];
21     tail -> left = build (p+1,s,i);
22     tail -> right = build (p+i+1,s+i+1,n-i-1);
23     return tail;
24 }
25 void downshow(struct tree *k)
26 {
27     if(k)
28     {
29         downshow(k -> left);
30         downshow(k -> right);
31         printf("%c",k -> l);
32     }
33 }
34 void stepshow(struct tree *k,char *p,int n)
35 {
36     int i,j,start,end,num;
37     struct tree *point[1000];
38     start = 0;
39     end = 0;
40     num = 0;
41     point[0] = k;
42     while(start < n)
43     {
44         j = 1;
45         for(i = start;i <= end;i ++)
46         {
47             p[i] = point[i] -> l;
48             if(point[i] -> left )
49             {
50                 point[end + j] = point[i] -> left;
51                 j ++;
52             }
53             if(point[i] -> right )
54             {
55                 point[end + j] = point[i] ->right;
56                 j ++;
57             }
58         }
59         start = end + 1;
60         end = end + j - 1;
61     }
62     p[n]='\0';
63 }
64 int main()
65 {
66     char str1[1000],str2[1000],str3[1000];
67     int t,l;
68     struct tree *head;
69     scanf("%d",&t);
70     while(t--)
71     {
72         memset(str3,0,sizeof(str3));
73         scanf("%s%s",str1,str2);
74         l = strlen(str1);
75         head = build(str1,str2,l);
76         downshow(head);
77         printf("\n");
78         stepshow(head,str3,l);
79         printf("%s\n",str3);
80     }
81     return 0;
82 }

 

posted @ 2012-05-28 19:07  Naix_x  阅读(204)  评论(0)    收藏  举报