Invert Binary Tree

Author: TonyKim9401

invert-binary-tree/TonyKim9401.java

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+// TC: O(n)
+// -> visit all nodes to invert
+// SC: O(n)
+// -> create all nodes again to exchange
+class Solution {
+    public TreeNode invertTree(TreeNode root) {
+        if (root == null) return null;
+        invertTree(root.left);
+        invertTree(root.right);
+        TreeNode left = root.left;
+        TreeNode right = root.right;
+        root.left = right;
+        root.right = left;
+        return root;
+    }
+}