二叉树问题，C代码，使用malloc

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

// 定义二叉树节点结构
struct TreeNode {
    int val;
    struct TreeNode* left;
    struct TreeNode* right;
};

// 创建二叉树节点
struct TreeNode* createNode(int val) {
    struct TreeNode* node = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    node->val = val;
    node->left = NULL;
    node->right = NULL;
    return node;
}

int main() {
    // 创建一个二叉树节点
    struct TreeNode* root = createNode(1);
    root->left = createNode(2);
    root->right = createNode(3);

    // 打印二叉树节点的值
    printf("Root: %d\n", root->val);
    printf("Left Child: %d\n", root->left->val);
    printf("Right Child: %d\n", root->right->val);

    // 释放内存
    free(root->left);
    free(root->right);
    free(root);

    return 0;
}