对称二叉树

package main

import "fmt"

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func isSymmetric(root *TreeNode) bool {
	if root == nil {
		return true
	}
	return isMirror(root.Left, root.Right)
}

func isMirror(left, right *TreeNode) bool {
	if left == nil && right == nil {
		return true
	}
	if left == nil || right == nil {
		return false
	}
	return left.Val == right.Val && isMirror(left.Left, right.Right) && isMirror(left.Right, right.Left)
}

func main() {
	// 创建一个对称二叉树
	root := &TreeNode{Val: 1}
	root.Left = &TreeNode{Val: 2}
	root.Right = &TreeNode{Val: 2}
	root.Left.Left = &TreeNode{Val: 3}
	root.Left.Right = &TreeNode{Val: 4}
	root.Right.Left = &TreeNode{Val: 4}
	root.Right.Right = &TreeNode{Val: 3}

	// 判断二叉树是否对称
	result := isSymmetric(root)

	// 输出结果
	fmt.Println(result)
}