Objective-C 中的二叉树

使用Objective-C语言来实现二叉树是一种常见的数据结构操作。二叉树是一种特殊的树形结构，它的每个节点最多只能有两个子节点，分别称为左子节点和右子节点。在Objective-C中，我们可以使用类来表示二叉树的节点，并通过节点间的链接来组织整个树结构。

objective-c
@interface BinaryTreeNode : NSObject
@property (nonatomic, strong) id value;
@property (nonatomic, strong) BinaryTreeNode *leftNode;
@property (nonatomic, strong) BinaryTreeNode *rightNode;
@end
@implementation BinaryTreeNode
@end

objective-c
BinaryTreeNode *createBinaryTree() {
    BinaryTreeNode *rootNode = [[BinaryTreeNode alloc] init];
    rootNode.value = @(1);
    
    BinaryTreeNode *leftNode = [[BinaryTreeNode alloc] init];
    leftNode.value = @(2);
    rootNode.leftNode = leftNode;
    
    BinaryTreeNode *rightNode = [[BinaryTreeNode alloc] init];
    rightNode.value = @(3);
    rootNode.rightNode = rightNode;
    
    BinaryTreeNode *leftLeftNode = [[BinaryTreeNode alloc] init];
    leftLeftNode.value = @(4);
    leftNode.leftNode = leftLeftNode;
    
    BinaryTreeNode *leftRightNode = [[BinaryTreeNode alloc] init];
    leftRightNode.value = @(5);
    leftNode.rightNode = leftRightNode;
    
    return rootNode;
}

objective-c
void preOrderTraversal(BinaryTreeNode *node) {
    if (node != nil) {
        NSLog(@"%@", node.value);
        preOrderTraversal(node.leftNode);
        preOrderTraversal(node.rightNode);
    }
}

objective-c
BinaryTreeNode *createContactTree() {
    BinaryTreeNode *rootNode = [[BinaryTreeNode alloc] init];
    rootNode.value = @{@"name": @"John", @"phone": @"1234567890"};
    
    BinaryTreeNode *leftNode = [[BinaryTreeNode alloc] init];
    leftNode.value = @{@"name": @"Alice", @"phone": @"0987654321"};
    rootNode.leftNode = leftNode;
    
    BinaryTreeNode *rightNode = [[BinaryTreeNode alloc] init];
    rightNode.value = @{@"name": @"Bob", @"phone": @"9876543210"};
    rootNode.rightNode = rightNode;
    
    return rootNode;
}