add: InvertBinaryTreeRecursive and InvertBinaryTreeIterative

Author: Jer3myYu

java/Trees/InvertBinaryTreeIterative.java

@@ -0,0 +1,40 @@
+import java.util.Stack;
+
+import DS.TreeNode;
+
+/*
+    // Definition of TreeNode:
+    class TreeNode {
+        public int val;
+        public TreeNode left;
+        public TreeNode right;
+        public TreeNode(int val) {
+            this.val = val;
+        }
+    }
+ */
+
+public class InvertBinaryTreeIterative {
+    public TreeNode invertBinaryTreeIterative(TreeNode root) {
+        if (root == null) {
+            return null;
+        }
+        Stack<TreeNode> stack = new Stack<>();
+        stack.push(root);
+        while (!stack.isEmpty()) {
+            TreeNode node = stack.pop();
+            // Swap the left and right subtrees of the current node.
+            TreeNode tmp = node.left;
+            node.left = node.right;
+            node.right = tmp;
+            // Push the left and right subtrees onto the stack.
+            if (node.left != null) {
+                stack.push(node.left);
+            }
+            if (node.right != null) {
+                stack.push(node.right);
+            }
+        }
+        return root;
+    }
+}

java/Trees/InvertBinaryTreeRecursive.java

@@ -0,0 +1,30 @@
+import DS.TreeNode;
+
+/*
+    // Definition of TreeNode:
+    class TreeNode {
+        public int val;
+        public TreeNode left;
+        public TreeNode right;
+        public TreeNode(int val) {
+            this.val = val;
+        }
+    }
+ */
+
+public class InvertBinaryTreeRecursive {
+    public TreeNode invertBinaryTreeRecursive(TreeNode root) {
+        // Base case: If the node is null, there's nothing to invert.
+        if (root == null) {
+            return root;
+        }
+        // Swap the left and right subtrees of the current node.
+        TreeNode tmp = root.left;
+        root.left = root.right;
+        root.right = tmp;
+        // Recursively invert the left and right subtrees.
+        invertBinaryTreeRecursive(root.left);
+        invertBinaryTreeRecursive(root.right);
+        return root;
+    }
+}