Is subtree of another tree

Author: shashankvishwakarma

src/main/java/dsa/trees/BinaryTree.java

@@ -80,7 +80,7 @@ private void populate(Scanner scanner, Node node) {
 
     public Node buildPreOrderTree(int[] nodes) {
         idx++;
-        if (nodes[idx] == -1) {
+        if (nodes.length <= idx || nodes[idx] == -1) {
             return null;
         }
         Node newNode = new Node(nodes[idx]);

src/main/java/leetcode/easy/SubtreeOfAnotherTree.java

@@ -0,0 +1,57 @@
+package leetcode.easy;
+
+import dsa.trees.BinarySearchTreeTraversal;
+import dsa.trees.BinaryTree;
+
+/**
+ * https://leetcode.com/problems/subtree-of-another-tree/description/
+ * <p>
+ * Example 1:
+ * Input: root = [3,4,5,1,2], subRoot = [4,1,2]
+ * Output: true
+ * <p>
+ * Example 2:
+ * Input: root = [3,4,5,1,2,null,null,null,null,0], subRoot = [4,1,2]
+ * Output: false
+ */
+class SubtreeOfAnotherTree {
+
+    public static void main(String[] args) {
+        BinarySearchTreeTraversal binarySearchTreeTraversal = new BinarySearchTreeTraversal();
+
+        int[] rootElements = {3, 4, 5, 1, 2};
+        int[] subRootElements = {4, 1, 2};
+
+        BinaryTree.Node rootNode = binarySearchTreeTraversal.buildPreOrderTree(rootElements);
+        BinaryTree.Node subRootNode = binarySearchTreeTraversal.buildPreOrderTree(subRootElements);
+
+        System.out.println("Is subtree of another tree " + isSubtree(rootNode, subRootNode));//Output: true
+    }
+
+    public static boolean isSubtree(BinaryTree.Node root, BinaryTree.Node subRoot) {
+        if (subRoot == null) {
+            return true;
+        }
+        if (root == null) {
+            return false;
+        }
+        if (isIdentical(root, subRoot)) {
+            return true;
+        }
+        return isSubtree(root.getLeft(), subRoot) || isSubtree(root.getRight(), subRoot);
+    }
+
+    public static boolean isIdentical(BinaryTree.Node root, BinaryTree.Node subRoot) {
+        if (subRoot == null && root == null) {
+            return true;
+        }
+        if (root == null || subRoot == null) {
+            return false;
+        }
+        if (root.getValue() == subRoot.getValue()) {
+            return isIdentical(root.getLeft(), subRoot.getLeft()) && isIdentical(root.getRight(), subRoot.getRight());
+        }
+        return false;
+    }
+
+}