平衡二叉树——A1066.RootofAVLTree（25）注意求平衡因子的函数，更新树高的函数，左旋和右旋的对称性：互换rchild与lchild即可，注意哪些函数需要用引用，哪些不需要

#include
#include
#include
#include
using namespace std;
const int maxn = 110;
struct node{
int v,height;
node *lchild,*rchild;
}*root;
//生成新节点,v为节点权值
node *newNode(int v){
node* Node = new node;
Node->v = v;
Node->height = 1;
Node->lchild = NULL;
Node->rchild = NULL;
return Node;
}
//获取以root为根节点的子树的当前height
int getHeight(node *root){
if(root == NULL){
return 0;
}else{
return root->height;
}
}
//更新节点root的height
void updateHeight(node* root){
root->height = max(getHeight(root->lchild),getHeight(root->rchild)) + 1;
}
//计算节点的平衡因子
int getBalanceFactor(node* root){
return getHeight(root->lchild) - getHeight(root->rchild);
}
//左旋
void L(node* &root){
node *temp = root->rchild;
root->rchild = temp->lchild;
temp->lchild = root;
updateHeight(root);
updateHeight(temp);
root = temp;
}
//右旋
void R(node* &root){
node *temp = root->lchild;
root->lchild = temp->rchild;
temp->rchild = root;
updateHeight(root);
updateHeight(temp);
root = temp;
}
//插入权值为v的节点
void insert(node* &root,int v){
if(root == NULL){
root = newNode(v);
return;
}
if(v v){
insert(root->lchild,v);
updateHeight(root);
if(getBalanceFactor(root) == 2){
if(getBalanceFactor(root->lchild) == 1){//LL型
R(root);
}else if(getBalanceFactor(root->lchild) == -1){
L(root->lchild);
R(root);
}
}
}
else{
insert(root->rchild,v);
updateHeight(root);
if(getBalanceFactor(root) == -2){
if(getBalanceFactor(root->rchild) == -1){
L(root);
}else if(getBalanceFactor(root->rchild) == 1){
R(root->rchild);
L(root);
}
}
}
}
//AVL树的建立
node *Create(int data[],int n){
node* root = NULL;
for(int i = 0;i insert(root,data[i]);
}
return root;
}
int main(){
int n,v;
scanf("%d",&n);
for(int i=0;i scanf("%d",&v);
insert(root,v);
}
printf("%d\n",root->v);
system("pause");
return 0;
}