AVL樹建立 1066

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <map>
using namespace std;

struct node  //建立節點
{
    int v,height;
    node* l;
    node* r;
};

node* creatN(int x)  //創建新節點
{
    node* root = new node;
    root ->l = root->r = NULL;
    root ->v = x;
    root ->height = 1;
    return root;
}

int getH(node* root)  //得到子樹高度
{
    if(root == NULL) return 0;
    else return root->height;
}

void updateH(node* &root)  //更新子樹高度
{
    root->height = max(getH(root->l),getH(root->r)) + 1;
}

void Lrotation(node* &root) //左旋
{
    node* temp = root->r;
    root->r = temp->l;
    temp->l = root;
    updateH(root); //別忘了更新高度
    updateH(temp);
    root = temp;
}

void Rrotation(node* &root) //右旋
{
    node* temp = root->l;
    root->l = temp->r;
    temp->r = root;
    updateH(root); //別忘了更新高度
    updateH(temp);
    root = temp;
}

int getbalance(node* root) //得到平衡因子
{
    return (getH(root->l) - getH(root->r));
}

void insertN(node* &root,int x) //插入
{
    if(root == NULL)
    {
        root = creatN(x);
        return;
    }
    if(x < root->v)
    {
        insertN(root->l,x);
        updateH(root);
        if(getbalance(root) == 2) 
        {
            if(getbalance(root->l) == 1) //LL型
                Rrotation(root); //轉移根節點
            else if(getbalance(root->l) == -1) //LR
            {
                Lrotation(root->l); //注意轉移節點
                Rrotation(root);
            }
        }

    }
    else if(x > root->v)
    {
        insertN(root->r,x);
        updateH(root);
        if(getbalance(root) == -2)
        {
            if(getbalance(root->r) == -1) //RR
                Lrotation(root); //轉移根節點
            else if(getbalance(root->r) == 1) //RL
            {
                Rrotation(root->r); //注意轉移節點
                Lrotation(root);
            }
        }
    }
}

int n;
int main()
{
    freopen("1.txt","r",stdin);
    scanf("%d",&n);
    node* root = new node;
    root = NULL;
    for(int i = 0;i<n;i++)
    {
        int t;
        scanf("%d",&t);
        insertN(root,t);
    }
    printf("%d",root->v);
}