Chapter 5 trees and binary trees

The basic concept of tree

1. The number of words owned by a node is called the degree of the node ; The maximum degree of each node in a tree is called the degree of the tree .
2. The number of sides on the path is the path length .
3. Specify the number of layers of the root node as 1, The maximum number of levels of all nodes in a tree is called the depth of the tree ; The maximum number of nodes in each layer in the book is called the width of the tree .

Be careful ： In order to uniquely determine a binary tree, there must be a middle order in two sequences .
Determine a tree according to its front order and middle order ：

Binode* Create_pre(char *pre,char *mid,int ipre,int imid,int n)
{
    
	if(n==0)
	return NULL;
	Binode *p=new Binode;
	p->data=pre[ipre];
	int i=0;
	while(pre[ipre]!=mid[imid+i]) i++;
	p->lc=Create_pre(pre,mid,ipre+1,imid,i);
	p->rc=Create_pre(pre,mid,ipre+i+1,imid+i+1,n-i-1);
	return p;
}

Determine the height of the tree ：

int Height(Binode* p)
{
    
    if(p==NULL)
        return 0;
    int left,right;
    left=Height(p->lc);
    right=Height(p->rc);
    if(left>right)
        return left+1;
    else
        return right+1;
}