leetcode-go/easy/226.invert-binary-tree.go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func invertTree(root *TreeNode) *TreeNode {
	if root == nil {
		return nil
	}
	ltree, rtree := invertTree(root.Left), invertTree(root.Right)
	root.Left, root.Right = rtree, ltree
	return root
}