3. 平衡二叉树

  程序输入一个字符串（只包含小写字母），请按照字符的输入顺序建立平衡二叉排序树，并分别输出二叉树的先序序列、中序序列和后序序列，最后输出该二叉树向左旋转 90 度后的结构。

例如：向左旋转 90 度后，以每层向里缩进 4 个空格的方式输出，输出结果为：

        i
    g
        f
a
        d
    c
        b

输入：agxnzyimk

输出：
Preorder: xigamknzy
Inorder: agikmnxyz
Postorder: agknmiyzx
Tree:
    z
        y
x
            n
        m
            k
    i
        g
            a

	测试输入	期待的输出	时间限制	内存限制	额外进程
测试用例 1	以文本方式显示 agxnzyimk↵	以文本方式显示 Preorder: xigamknzy↵ Inorder: agikmnxyz↵ Postorder: agknmiyzx↵ Tree:↵     z↵         y↵ x↵             n↵         m↵             k↵     i↵         g↵             a↵	1秒	64M	0
测试用例 2	以文本方式显示 asdfghjkl↵	以文本方式显示 Preorder: gdafjhlks↵ Inorder: adfghjkls↵ Postorder: afdhksljg↵ Tree:↵             s↵         l↵             k↵     j↵         h↵ g↵         f↵     d↵         a↵	1秒	64M	0

 代码如下（上个忘了说了，以后就尽量都用C++写了）

        C++写着确实输入，当然树这块一般，至少二叉树一般，最大的问题是每次交乐学都忘换编译语言。

#include 
#include 
#include 
using namespace std;
struct AVLnode
{
    char data;
    AVLnode *left;
    AVLnode *right;
};
AVLnode *root = NULL;
int depth(AVLnode *root)
{
    if (root == NULL)
        return 0;
    else
    {
        if (depth(root->left) > depth(root->right))
            return depth(root->left) + 1;
        else
            return depth(root->right) + 1;
    }
}
AVLnode *LL(AVLnode *root)
{
    AVLnode *son = root->left;
    root->left = son->right;
    son->right = root;
    return son;
}
AVLnode *RR(AVLnode *root)
{
    AVLnode *son = root->right;
    root->right = son->left;
    son->left = root;
    return son;
}
AVLnode *RL(AVLnode *root)
{
    AVLnode *son = root->right;
    root->right = LL(son);
    return RR(root);
    // 嵌套
    // AVLnode *son = root->right, *r = son->left;
	// son->left = r->right;
	// r->right = son;
	// root->right = r->left;
	// r->left = root;
	// return r;
}
AVLnode *LR(AVLnode *root)
{
    AVLnode *son = root->left;
    root->left = RR(son);
    return LL(root);
    // AVLnode *son = root->left, *r = son->right;
	// son->right = r->left;
	// r->left = son;
	// root->left = r->right;
	// r->right = root;
	// return r;
}
AVLnode *Initialize(char Data)
{
    AVLnode *Node = (AVLnode *)malloc(sizeof(AVLnode));
    Node->data = Data;
    Node->left = NULL;
    Node->right = NULL;
    return Node;
}
AVLnode *insertNode(AVLnode *root, char Data)
{
    if (root == NULL)
    {
        root = Initialize(Data);
        return root;
    }
    else
    {
        if (Data < root->data)
        {
            root->left = insertNode(root->left, Data);
            if (depth(root->left) - depth(root->right) > 1)
            {
                if (Data < root->left->data)
                    root = LL(root);
                else
                    root = LR(root);
            }
        }
        else
        {
            root->right = insertNode(root->right, Data);
            if (depth(root->right) - depth(root->left) > 1)
            {
                if (Data < root->right->data)
                    root = RL(root);
                else
                    root = RR(root);
            }
        }
    }
    return root;
}
void printPreOrder(AVLnode *root)
{
    if (root != NULL)
    {
        cout << root->data;
        printPreOrder(root->left);
        printPreOrder(root->right);
    }
}
void printInOrder(AVLnode *root)
{
    if (root != NULL)
    {
        printInOrder(root->left);
        cout << root->data;
        printInOrder(root->right);
    }
}
void printPostOrder(AVLnode *root)
{
    if (root != NULL)
    {
        printPostOrder(root->left);
        printPostOrder(root->right);
        cout << root->data;
    }
}
void AVLprint(AVLnode *root, int space)
{
	if (root->right)
		AVLprint(root->right, space + 4);
	for (int i = 0; i < space; i++)
		cout << " ";
	cout << root->data << endl;
	if (root->left)
		AVLprint(root->left, space + 4);
}
int main()
{
    string input;
    getline(cin, input);
    for (char c : input)
    {
        if (c == '\n')
            break;
        root = insertNode(root, c);
    }
    cout << "Preorder: ";
    printPreOrder(root);
    cout << "\nInorder: ";
    printInOrder(root);
    cout << "\nPostorder: ";
    printPostOrder(root);
    cout << "\nTree:\n";
    AVLprint(root, 0);
    return 0;
}