最基础的算法练习2

恢复二叉树

 1 #include <fstream>
 2 #include <iostream>
 3
 4 using namespace std;
 5
 6 struct node
 7 {
 8     char c;
 9     struct node *lch,*rch;
10 };
11
12 int count_leaf(node* tree);//统计叶子结点
13 int count_deep(node* tree);//统计树的深度
14 void create_tree(char* l,char* r,int i,int j,int e,int f,node** tree);//由先序遍历序列和中序遍历序列恢复二叉树
15
16 int main()
17 {
18     //freopen("D:\\input.in","r",stdin);
19     //freopen("D:\\output.out","w",stdout);
20     node *tree;cout<<int(tree)<<endl<<int(&tree)<<endl;
21     char pre[]="ABDGCEF";
22     char in[]="DGBAECF";
23     create_tree(pre,in,0,6,0,6,&tree);
24     cout<<count_leaf(tree)<<endl;
25     cout<<count_deep(tree)<<endl;
26     return 0;
27 }
28 int count_leaf(node* tree)
29 {
30     if(tree==NULL)  return 0;
31     if(tree->lch==NULL&&tree->rch==NULL)    return 1;
32     return count_leaf(tree->lch)+count_leaf(tree->rch);
33 }
34 int count_deep(node* tree)
35 {
36     if(tree==NULL)  return 0;
37     return 1+max(count_deep(tree->lch),count_deep(tree->rch));
38 }
39 void create_tree(char* l,char* r,int i,int j,int e,int f,node** tree)
40 {
41     int m;
42     (*tree)=new node;
43     (*tree)->c=l[i];
44     m=e;
45     while(r[m]!=l[i])    m++;
46     if(m==e)    (*tree)->lch=NULL;
47     else    create_tree(l,r,i+1,i+m-e,e,m-1,&(*tree)->lch);
48     if(m==f)    (*tree)->rch=NULL;
49     else    create_tree(l,r,i+m-e+1,j,m+1,f,&(*tree)->rch);
50 }