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diff --git a/Collapse file
‎src/main/java/com/eprogrammerz/examples/algorithm/trees/CheckSubtree.java‎
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+9Lines changed: 9 additions & 0 deletions b/Collapse file
‎src/main/java/com/eprogrammerz/examples/algorithm/trees/CheckSubtree.java‎
Copy file name to clipboardExpand all lines: src/main/java/com/eprogrammerz/examples/algorithm/trees/CheckSubtree.java
+9Lines changed: 9 additions & 0 deletions
diff --git a/Collapse file
‎src/main/java/com/eprogrammerz/examples/algorithm/trees/Node.java‎
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+5-21Lines changed: 5 additions & 21 deletions b/Collapse file
‎src/main/java/com/eprogrammerz/examples/algorithm/trees/Node.java‎
Copy file name to clipboardExpand all lines: src/main/java/com/eprogrammerz/examples/algorithm/trees/Node.java
+5-21Lines changed: 5 additions & 21 deletions
@@ -49,5 +49,14 @@ public void testSubtree() {
          */
         that.left.right = new Node(10);
         assertFalse(root.isSubtree(that));
+
+        /**
+         *      15
+         *     /
+         *   17
+         */
+        Node another = new Node(15);
+        another.left = new Node(17);
+        assertFalse(root.isSubtree(another));
     }
 }
@@ -71,10 +71,9 @@ public boolean validate() {
     public boolean isSubtree(Node that) {
         // do bfs on this
         // if node found same as of that.root
-        // then clear the queue of tree
-        // start bfs for both, each queue poll should match
+        // then traverse tree and see if left and right on both trees match
 
-        if (that == null) return false;
+        if (that == null) return true;
 
         Queue<Node> thisQueue = new LinkedList<>();
         thisQueue.add(this);
@@ -99,26 +98,11 @@ public boolean isSubtree(Node that) {
     }
 
     private boolean isSubtree(Node t1, Node t2) {
+        if (t1 == null && t2 == null) return true;
 
-        Queue<Node> t1Queue = new LinkedList<>();
-        t1Queue.add(t1);
+        if (t1 == null || t2 == null || t1.data != t2.data) return false;
 
-        Queue<Node> t2Queue = new LinkedList<>();
-        t2Queue.add(t2);
-
-        while (!t1Queue.isEmpty() && !t2Queue.isEmpty()) {
-            Node t1Node = t1Queue.poll();
-            Node t2Node = t2Queue.poll();
-
-            if (t1Node.data != t2Node.data) return false;
-
-            if (t1Node.left != null) t1Queue.add(t1Node.left);
-            if (t1Node.right != null) t1Queue.add(t1Node.right);
-
-            if (t2Node.left != null) t2Queue.add(t2Node.left);
-            if (t2Node.right != null) t2Queue.add(t2Node.right);
-        }
-        return t1Queue.isEmpty() && t2Queue.isEmpty();
+        return isSubtree(t1.left, t2.left) && isSubtree(t1.right, t2.right);
     }
 
     @Override