Hello, World!

对称二叉树

// isSymmetric
package isSymmetric

//Definition for a binary tree node.
type TreeNode struct {
 Val   int
 Left  *TreeNode
 Right *TreeNode
}

func isSymmetric(root *TreeNode) bool {
 return _isSymmetric(root, root)
}

func _isSymmetric(left, right *TreeNode) bool {
 if left == nil && right == nil {
  return true
 }
 if left != nil || right != nil {
  return false
 }

 return _isSymmetric(left.Left, right.Right) && _isSymmetric(right.Left, left.Right) && left.Val == right.Val

}