Merge pull request #1795 from akgmage/dev

add bt invert in java and js

Author: akgmage

Trees/Binary Trees/invert.java

@@ -0,0 +1,61 @@
+class BinaryTreeNode {
+    int data;
+    BinaryTreeNode left, right;
+
+    public BinaryTreeNode(int data) {
+        this.data = data;
+        this.left = this.right = null;
+    }
+}
+
+public class BinaryTreeInverter {
+    // Time Complexity: O(n). Space Complexity: O(n).
+    // Approach: The inverse of an empty tree is an empty tree
+    // The inverse of a tree with root r, and subtrees right and left is a tree with
+    // root, whose right subtree is the inverse of left and whose left subtree
+    // is the inverse of right
+    public BinaryTreeNode invertTree(BinaryTreeNode root) {
+        if (root != null) {
+            root.left = invertTree(root.right);
+            root.right = invertTree(root.left);
+        }
+        return root;
+    }
+
+    // Time Complexity: O(n). Space Complexity: O(1).
+    // Method2: swap pointers
+    public BinaryTreeNode invertTree2(BinaryTreeNode root) {
+        if (root != null) {
+            // swap the pointers in this node
+            BinaryTreeNode temp = root.left;
+            root.left = root.right;
+            root.right = temp;
+
+            invertTree2(root.left);
+            invertTree2(root.right);
+        }
+        return root;
+    }
+
+    // Additional methods or code as needed...
+
+    public static void main(String[] args) {
+        // Example usage:
+        // Construct a binary tree
+        BinaryTreeNode root = new BinaryTreeNode(1);
+        root.left = new BinaryTreeNode(2);
+        root.right = new BinaryTreeNode(3);
+        root.left.left = new BinaryTreeNode(4);
+        root.left.right = new BinaryTreeNode(5);
+
+        BinaryTreeInverter inverter = new BinaryTreeInverter();
+
+        // Invert the binary tree using the first approach
+        BinaryTreeNode invertedRoot = inverter.invertTree(root);
+
+        // Invert the binary tree using the second approach
+        BinaryTreeNode invertedRoot2 = inverter.invertTree2(root);
+
+        // Additional code for printing or further usage...
+    }
+}

Trees/Binary Trees/invert.js

@@ -0,0 +1,61 @@
+class BinaryTreeNode {
+  constructor(data) {
+    this.data = data;
+    this.left = this.right = null;
+  }
+}
+
+class BinaryTreeInverter {
+  // Time Complexity: O(n). Space Complexity: O(n).
+  // Approach: The inverse of an empty tree is an empty tree
+  // The inverse of a tree with root r, and subtrees right and left is a tree with
+  // root, whose right subtree is the inverse of left and whoose left subtree
+  // is the inverse of right
+  invertTree(root) {
+    if (root !== null) {
+      root.left = this.invertTree(root.right);
+      root.right = this.invertTree(root.left);
+    }
+    return root;
+  }
+
+  // Time Complexity: O(n). Space Complexity: O(1).
+  // Method2: swap pointers
+  invertTree2(root) {
+    if (root !== null) {
+      // swap the pointers in this node
+      let temp = root.left;
+      root.left = root.right;
+      root.right = temp;
+
+      this.invertTree2(root.left);
+      this.invertTree2(root.right);
+    }
+    return root;
+  }
+
+  // Additional methods or code as needed...
+
+  // Example usage:
+  static main() {
+    // Construct a binary tree
+    let root = new BinaryTreeNode(1);
+    root.left = new BinaryTreeNode(2);
+    root.right = new BinaryTreeNode(3);
+    root.left.left = new BinaryTreeNode(4);
+    root.left.right = new BinaryTreeNode(5);
+
+    let inverter = new BinaryTreeInverter();
+
+    // Invert the binary tree using the first approach
+    let invertedRoot = inverter.invertTree(root);
+
+    // Invert the binary tree using the second approach
+    let invertedRoot2 = inverter.invertTree2(root);
+
+    // Additional code for printing or further usage...
+  }
+}
+
+// Example usage:
+BinaryTreeInverter.main();