easy
1 class Solution { 2 public TreeNode invertTree(TreeNode root) { 3 if(root == null) return root; 4 TreeNode newRoot = new TreeNode(0); 5 newRoot = invertTree(root.left); 6 root.left = invertTree(root.right); 7 root.right = newRoot; 8 return root; 9 10 } 11 }