PTA AVL Insertion

You are supposed to implement the Insert function, which inserts an integer Key into an AVL tree T. The resulting tree must be returned.

Format of function:

AVLTree Insert ( AVLTree T, int Key );

where AVLTree is defined as the following:

typedef struct AVLNode *PtrToAVLNode;
struct AVLNode{
    int Key;
    PtrToAVLNode Left;
    PtrToAVLNode Right;
    int Height;
};
typedef PtrToAVLNode AVLTree;

Sample program of judge:

#include <stdio.h>
#include <stdlib.h>

typedef struct AVLNode *PtrToAVLNode;
struct AVLNode{
    int Key;
    PtrToAVLNode Left;
    PtrToAVLNode Right;
    int Height;
};
typedef PtrToAVLNode AVLTree;

AVLTree Insert ( AVLTree T, int Key );
void PostOrderPrint( AVLTree T ); /* details omitted */
void InOrderPrint( AVLTree T );   /* details omitted */

int main()
{
    int N, Key, i;
    AVLTree T = NULL;

    scanf("%d", &N);
    for ( i=0; i<N; i++ ) {
        scanf("%d", &Key);
        T = Insert( T, Key );
    }
    PostOrderPrint( T );
    InOrderPrint( T );

    return 0;
}
/* Your function will be put here */

Sample Input:

7
88 70 61 96 120 90 65

Sample Output:

Post-order: 61 70 65 90 120 96 88
In-order: 61 65 70 88 90 96 120

代码：

int height(AVLTree T) 
{
    AVLTree l = T->Left;
    AVLTree r = T->Right;
    if (r == NULL&&l == NULL)
        return 1;
    else if (r == NULL&&l != NULL) 
        return l->Height + 1;
    else if (r != NULL&&l == NULL) 
        return r->Height + 1;
    else 
    {
        if (r->Height > l->Height) 
            return r->Height + 1;
        else 
            return l->Height + 1;
    }
}
int judge(AVLTree T)
{
    int r = 0, l = 0;
    if (T->Left != NULL) 
        l = T->Left->Height;
    if (T->Right != NULL) 
        r = T->Right->Height;
    return l - r;
}
AVLTree Insert(AVLTree T, int Key) 
{
    if (T == NULL) 
    {
        T = (AVLTree)malloc(sizeof(struct AVLNode));
        T->Left = T->Right = NULL; 
        T->Key = Key; 
        T->Height = 1;
    }
    else 
    {
        if (T->Key > Key)  
            T->Left = Insert(T->Left, Key);
        else if (T->Key < Key)
            T->Right = Insert(T->Right,Key);
        T->Height = height(T);
        if (judge(T) > 1) 
        {
            AVLTree l = T->Left;
            if (judge(l) >0) 
            {  
                T->Left = l->Right;
                l->Right = T;
                T = l;
                T->Right->Height = height(T->Right);
            }
            else if(judge(l) <0)
            {
                AVLTree r = l->Right;
                l->Right = r->Left;
                r->Left = l;
                l = r;
                T->Left = l->Right;
                l->Right = T;
                T = l;
                T->Left->Height = height(T->Left);
                T->Right->Height = height(T->Right);
            }  
            T->Height = height(T);
        }
        else if (judge(T)<-1) 
        { 
            AVLTree r = T->Right;
            if (judge(r) >0) 
            { 
                AVLTree l = r->Left;
                r->Left = l->Right;
                l->Right = r;
                r = l;
                T->Right = r->Left;
                r->Left = T;
                T = r;
                T->Left->Height = height(T->Left);
                T->Right->Height = height(T->Right);
            }
            else if (judge(r) <0) 
            {
                T->Right = r->Left;
                r->Left = T;
                T = r;
                T->Left->Height = height(T->Left);
            }
            T->Height = height(T);
        }
    }
    return T;
} 

提交结果：