带有迭代插入的C语言AVL树

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

// AVL树节点结构
struct Node {
    int key;
    struct Node* left;
    struct Node* right;
    int height;
};

// 获取节点的高度
int getHeight(struct Node* node) {
    if (node == NULL)
        return 0;
    return node->height;
}

// 获取两个数中较大的数
int max(int a, int b) {
    return (a > b) ? a : b;
}

// 创建一个新节点
struct Node* createNode(int key) {
    struct Node* node = (struct Node*)malloc(sizeof(struct Node));
    node->key = key;
    node->left = NULL;
    node->right = NULL;
    node->height = 1;
    return node;
}

// 右旋操作
struct Node* rightRotate(struct Node* y) {
    struct Node* x = y->left;
    struct Node* T2 = x->right;

    x->right = y;
    y->left = T2;

    y->height = max(getHeight(y->left), getHeight(y->right)) + 1;
    x->height = max(getHeight(x->left), getHeight(x->right)) + 1;

    return x;
}

// 左旋操作
struct Node* leftRotate(struct Node* x) {
    struct Node* y = x->right;
    struct Node* T2 = y->left;

    y->left = x;
    x->right = T2;

    x->height = max(getHeight(x->left), getHeight(x->right)) + 1;
    y->height = max(getHeight(y->left), getHeight(y->right)) + 1;

    return y;
}

// 获取平衡因子
int getBalanceFactor(struct Node* node) {
    if (node == NULL)
        return 0;
    return getHeight(node->left) - getHeight(node->right);
}

// 插入节点
struct Node* insertNode(struct Node* node, int key) {
    // 执行标准的BST插入
    if (node == NULL)
        return createNode(key);

    if (key < node->key)
        node->left = insertNode(node->left, key);
    else if (key > node->key)
        node->right = insertNode(node->right, key);
    else
        return node; // 不允许插入重复的节点

    // 更新节点的高度
    node->height = 1 + max(getHeight(node->left), getHeight(node->right));

    // 获取节点的平衡因子
    int balanceFactor = getBalanceFactor(node);

    // 如果节点不平衡，根据平衡因子进行旋转和调整
    if (balanceFactor > 1) {
        if (key < node->left->key) {
            // 左左情况，进行右旋
            return rightRotate(node);
        } else if (key > node->left->key) {
            // 左右情况，先左旋再右旋
            node->left = leftRotate(node->left);
            return rightRotate(node);
        }
    }

    if (balanceFactor < -1) {
        if (key > node->right->key) {
            // 右右情况，进行左旋
            return leftRotate(node);
        } else if (key < node->right->key) {
            // 右左情况，先右旋再左旋
            node->right = rightRotate(node->right);
            return leftRotate(node);
        }
    }

    return node;
}

// 中序遍历AVL树
void inorderTraversal(struct Node* root) {
    if (root != NULL) {
        inorderTraversal(root->left);
        printf("%d ", root->key);
        inorderTraversal(root->right);
    }
}

// 主函数
int main() {
    struct Node* root = NULL;

    // 插入节点
    root = insertNode(root, 10);
    root = insertNode(root, 20);
    root = insertNode(root, 30);
    root = insertNode(root, 40);
    root = insertNode(root, 50);
    root = insertNode(root, 25);

    // 中序遍历AVL树
    printf("AVL树中序遍历结果：");
    inorderTraversal(root);

    return 0;
}