平衡二叉树模板

 平衡二叉树模板

#include<iostream>
using namespace std;
struct node{
	int data,height;
	node* left;
	node* right;
};


node* newNode(int data){
	node* root = new node;
	root->data = data;
	root->height = 1;
	root->left = root->right = NULL;
	return root;
}


int getHeight(node* root){
	if(root == NULL){
		return 0;
	}
	return root->height;
}

int getBalance(node* root){
	return getHeight(root->left) - getHeight(root->right);
}

int updateHeight(node* root){
	return root->height =  max(getHeight(root->left),getHeight(root->right)) +1;
}

node * search(node* root,int data){
	if(root == NULL) return NULL;
	if(data == root->data) {
		printf("%d\n",root->data);
		return root;	
	}
	
	if(root->data > data)return search(root->left,data);
	else return search(root->right,data);
}


void L(node* &root){
	node * temp = root->right;
	root->right = temp->left;
	temp->left = root;
	updateHeight(root);
	updateHeight(temp);
	root =  temp;
}


void R(node * &root){
	node * temp = root->left;
	root->left = temp->right;
	temp->right = root;
	updateHeight(root);
	updateHeight(temp);
	root = temp;
}

void insert(node * &root,int v){
	if(root ==NULL){
		root = newNode(v); return;
	}
	if(v<root->data){
		insert(root->left,v);
		updateHeight(root);
		int ba = getBalance(root);
		if(ba == 2){
			int lba = getBalance(root->left);
			if(lba == 1){
				R(root);
			}else if (lba == -1){
				L(root->left);
				R(root);
			}
		}
	}else{
		insert(root->right,v);
		updateHeight(root);
		int ba = getBalance(root);
		if(ba == -2){
			int lba = getBalance(root->right);
			if(lba == -1){
				L(root);
			}else if (lba == 1){
				R(root->right);
				L(root);
			}
		}
	}
}

node* create(int arr[],int n){
	node* root = NULL;
	for(int i=0;i<n;i++){
		insert(root,arr[i]);
	}
	return root;
}

node * preorder(node* root){
	if(root == NULL) return NULL;
	
	printf("%d ",root->data);
	preorder(root->left);
	preorder(root->right);
}


int arr[10000];
int main(){
	
	int N;
	scanf("%d",&N);
	for(int i=0;i<N;i++){
		scanf("%d",&arr[i]);
	}
	
	node * root = create(arr, N);
	
	preorder(root);

	return 0;
}