【数据结构】 二叉树的基本操作

//二叉树
struct node{
	typename data;
	node *lchild;
	node *rchild;
}
//生成一个新节点，v为权值
node* newnode(int v){
	node* Node=new node;
	Node->data=v;
	Node->lchild=Node->rchild=NULL;
	return Node;
}
//修改值
void search(node* root,int x,int newdata){
	if(root==NULL) return;
	if(root->data==x){
		root->data=newdata;
	}
	search(root->lchild,x,newdata);
	search(root->rchild,x,newdata);
}
//插入
void insert(node* &root,int x){ //此处为引用
	if(root==NULL){				//空位置即为插入位置
		root=newnode(x);
		return;
	}
	if(插入左子树){
		insert(root->lchild,x);
	}else{
		insert(root->rchild,x);
	}
}
//创建
node *create(int data[],int n){
	node *root=NULL;
	for(int i=0;i<n;i++){
		insert(root,data[i]);
	}
 return root;
}
 //先序遍历
 void preOrder(Node* root)
 {
	if(root==NULL){
		return;
	}else{
	cout<<root->data<<' ';
	preOrder(root->Left);
	preOrder(root->Right);
	}
 }
 //中序遍历
 void inOrder(Node* root)
 {
	if(root==NULL){
		return;
	}else{
		inOrder(root->Left);
		cout<<root->data<<' ';
		inOrder(root->Right);
	}
 }
 //后序遍历
 void postOrder(Node* root)
 {
	if(root==NULL){
		return;
	}else{
		postOrder(root->Left);
		postOrder(root->Right);
		cout<<root->data<<' ';
	}
 }
 //层序遍历
 void LayerOrder(node *root){
	queue<node*> q;
	q.push(root);
	while(!q.empty){
		node* now=q.front();
		q.pop();
		cout<<now->data<<" ";
		if(now->lchild!=NULL)
			q.push(now->lchild);
		if(now->rchild!=NULL)
			q.push(now->rchild);
	}
 }
 //已知先序序列和中序序列，构建二叉树
 node *create(int preL,int preR,int inL,int inR)
 {
	if(preL>preR) return NULL;	//递归边界
	node *root=new node;
	root->data=pre[preL];
	int k;
	for(k=inL;k<=inR;k++){	//寻找中序序列中根节点的位置k
		if(in[k]==pre[preL]){
			break;
		}
	}
	int numLeft=k-inL;
	root->lchild=create(preL+1,preL+numLeft,inL,k-1);
	root->rchild=create(preL+numLeft+1,preR,k+1,inR);
	return root;
}
//已知中序序列和后序序列，构建二叉树
node *create(int postL,int postR,int inL,int inR)
{
	if(postL>postR) return NULL;
	node *root=new node;
	root->data=post[postR];
	int k;
	for(k=inL;k<=inR;k++){
		if(in[k]==post[postR]){
			break;
		}
	}
	int numLeft=k-inL;
	root->lchild=create(postL,postL+numLeft-1,inL,k-1);
	root->rchild=create(postL+numLeft,postR-1,k+1,inR);
	return root;
}
//二叉树节点总数目
int Nodenum(Node* root)
{
	if(root == NULL)
		return 0;
	else
		return 1+Nodenum(root->Left)+Nodenum(root->Right);
}
//二叉树深度
int DepthOfTree(Node* root)
{
	if(root)
	{
		if(DepthOfTree(root->Left)>DepthOfTree(root->Right))
			return DepthOfTree(root->Left)+1;
		else
			return DepthOfTree(root->Right)+1;
	}
	if( root == NULL )
		return 0;
}
//二叉树叶子节点数
int Leafnum(Node* root)
{
	if(root==NULL)
		return 0;
	else if((root->Left==NULL) && (root->Right==NULL))
		return 1;
	else
		return (Leafnum(root->Left)+Leafnum(root->Right)) ;
}