九度oj 题目1184 二叉树遍历

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<vector>
 5 struct node{
 6     char key;
 7     node *ch[2];
 8     node(char d) : key(d) { ch[0] = ch[1] = NULL; }
 9 }*root = NULL;
10 int n = 0;
11 static int k = -1;
12 char buf[110];
13 void built(node *&p){
14     k++;
15     if (k > n) return;
16     if (buf[k] != ‘#‘){
17         p = new node(buf[k]);
18         built(p->ch[0]);
19         built(p->ch[1]);
20     }
21 }
22 void travle(node *x){
23     if (x != NULL){
24         travle(x->ch[0]);
25         printf("%c ", x->key);
26         travle(x->ch[1]);
27     }
28 }
29 void _free(node *x){
30     if (x != NULL){
31         _free(x->ch[0]);
32         _free(x->ch[1]);
33         delete x;
34     }
35 }
36 int main(){
37 #ifdef LOCAL
38     freopen("in.txt", "r", stdin);
39     freopen("out.txt", "w+", stdout);
40 #endif
41     while (~scanf("%s", buf)){
42         k = -1, root = NULL, n = strlen(buf);
43         built(root);
44         travle(root);
45         _free(root);
46         printf("\n");
47     }
48     return 0;
49 }