平衡二叉树c语言实现代码

以下是一个简单的C语言实现平衡二叉树的代码，其中包括了对于四种不平衡情况的处理和递归添加新数据的方法：

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

typedef struct node {
    int data;
    struct node *left;
    struct node *right;
    int height;
} node;

int height(node *n) {
    if (n == NULL) {
        return 0;
    }
    return n->height;
}

int max(int a, int b) {
    return (a > b) ? a : b;
}

node *new_node(int data) {
    node *n = (node *)malloc(sizeof(node));
    n->data = data;
    n->left = NULL;
    n->right = NULL;
    n->height = 1;
    return n;
}

node *right_rotate(node *y) {
    node *x = y->left;
    node *T2 = x->right;

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

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

    return x;
}

node *left_rotate(node *x) {
    node *y = x->right;
    node *T2 = y->left;

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

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

    return y;
}

int get_balance(node *n) {
    if (n == NULL) {
        return 0;
    }
    return height(n->left) - height(n->right);
}

node *insert(node *n, int data) {
    if (n == NULL) {
        return new_node(data);
    }

    if (data < n->data) {
        n->left = insert(n->left, data);
    } else if (data > n->data) {
        n->right = insert(n->right, data);
    } else {
        return n;
    }

    n->height = 1 + max(height(n->left), height(n->right));

    int balance = get_balance(n);

    if (balance > 1 && data < n->left->data) {
        return right_rotate(n);
    }

    if (balance < -1 && data > n->right->data) {
        return left_rotate(n);
    }

    if (balance > 1 && data > n->left->data) {
        n->left = left_rotate(n->left);
        return right_rotate(n);
    }

    if (balance < -1 && data < n->right->data) {
        n->right = right_rotate(n->right);
        return left_rotate(n);
    }

    return n;
}

void pre_order(node *n) {
    if (n != NULL) {
        printf("%d ", n->data);
        pre_order(n->left);
        pre_order(n->right);
    }
}

int main() {
    node *root = NULL;

    root = insert(root, 10);
    root = insert(root, 20);
    root = insert(root, 30);
    root = insert(root, 40);
    root = insert(root, 50);
    root = insert(root, 25);

    printf("Preorder traversal of the constructed AVL tree is: \n");
    pre_order(root);

    return 0;
}