完全考察AVL树的建树，光看书感觉已经掌握了，结果敲的时候发现总会漏一些细节

#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
typedef struct AVLNode * Position;
typedef Position AVLTree;
typedef struct AVLNode{
    int Data;
    AVLTree Left;
    AVLTree Right;
    int Height;
};

int n;
int GetHeight(AVLTree t){
    if(t)
        return t->Height;
    else
        return 0;
}

AVLTree SingleLeftRotate(AVLTree a){
    AVLTree tmp = a->Left;
    a->Left = tmp->Right;//先把原左子树的右子树接到a
    tmp->Right = a;
    a->Height = max(GetHeight(a->Left), GetHeight(a->Right)) + 1;
    tmp->Height = max(GetHeight(tmp->Left), GetHeight(tmp->Right)) + 1;
    return tmp;
}

AVLTree SingleRightRotate(AVLTree a){
    AVLTree tmp = a->Right;
    a->Right = tmp->Left;
    tmp->Left = a;
    a->Height = max(GetHeight(a->Left), GetHeight(a->Right)) + 1;
    tmp->Height = max(GetHeight(tmp->Left), GetHeight(tmp->Right)) + 1;
    return tmp;
}

AVLTree DoubleLeftRightRotate(AVLTree a){
    a->Left = SingleRightRotate(a->Left);
    return SingleLeftRotate(a);
}

AVLTree DoubleRightLeftRotate(AVLTree a){
    a->Right = SingleLeftRotate(a->Right);
    return SingleRightRotate(a);
}

AVLTree InsertToTree(AVLTree t, int x){
    if(!t){
        t = (AVLTree)malloc(sizeof(struct AVLNode));
        t->Data = x;
        t->Height = 1;
        t->Left = t->Right = NULL;
    }
    else if(x < t->Data){
        t->Left = InsertToTree(t->Left,x);
        if(GetHeight(t->Left) - GetHeight(t->Right) == 2)
            if(x < t->Left->Data)//LL型
                t = SingleLeftRotate(t);
            else//LR型
                t = DoubleLeftRightRotate(t);
    }
    else if(x > t->Data){
        t->Right = InsertToTree(t->Right,x);
        if(GetHeight(t->Right) - GetHeight(t->Left) == 2)
            if(x > t->Right->Data)//RR型
                t = SingleRightRotate(t);
            else//RL型
                t = DoubleRightLeftRotate(t);
    }
    t->Height = max(GetHeight(t->Left), GetHeight(t->Right)) + 1;
    return t;
}
int main(){
    scanf("%d",&n);
    int d;
    AVLTree tree = NULL;
    for(int i = 0; i < n; ++i){
        scanf("%d",&d);
        tree = InsertToTree(tree,d);
    }
    printf("%d",tree->Data);
    return 0;
}