From 371c065e1ba9172870fe3145591286dcc111f86b Mon Sep 17 00:00:00 2001
From: marizvi <202051121@iiitvadodara.ac.in>
Date: Sun, 10 Oct 2021 22:54:17 +0530
Subject: [PATCH] reverse level order added

---
 binary_search_tree/revLevelOrder.java | 93 +++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 binary_search_tree/revLevelOrder.java

diff --git a/binary_search_tree/revLevelOrder.java b/binary_search_tree/revLevelOrder.java
new file mode 100644
index 00000000..3ee58ee1
--- /dev/null
+++ b/binary_search_tree/revLevelOrder.java
@@ -0,0 +1,93 @@
+package Binarytree;
+
+import java.util.*;
+
+class Nodes{
+    int data;
+    Nodes left;
+    Nodes right;
+    Nodes(int element)
+    {
+        this.data = element;
+        this.left = this.right = null;
+    }
+}
+
+class BST_REV{
+    Nodes root;
+    BST_REV()
+    {
+        root = null;
+    }
+    void addNode(int element)
+    {
+        root = add(root,element);
+    }
+    Nodes add(Nodes node, int element)
+    {
+        if(node == null)
+            return new Nodes(element);
+        if(element<=node.data)
+            node.left = add(node.left,element);
+        else
+        if(element>node.data)
+            node.right = add(node.right,element);
+
+        return node;
+    }
+
+    ArrayList<Integer> revLevelOrder()
+    {
+        return revLevelOrder(root);
+    }
+    ArrayList<Integer> levelOrder()
+    {
+        return levelOrder(root);
+    }
+    ArrayList <Integer> levelOrder(Nodes node)
+    {
+        ArrayList<Integer> al = new ArrayList<>();
+        Queue<Nodes> q = new LinkedList<>();
+        q.add(node);
+        while(!q.isEmpty()) {
+            Nodes temp = q.remove();
+            al.add(temp.data);
+            if(temp.left!=null)
+                q.add(temp.left);
+            if(temp.right!=null)
+                q.add(temp.right);
+        }
+        return al;
+    }
+    ArrayList <Integer> revLevelOrder(Nodes node)
+    {
+        ArrayList<Integer> al = new ArrayList<>();
+        Queue<Nodes> q = new LinkedList<>();
+        q.add(node);
+        while(!q.isEmpty()) {
+            Nodes temp = q.remove();
+            al.add(temp.data);
+            if(temp.right!=null)
+                q.add(temp.right);
+            if(temp.left!=null)
+                q.add(temp.left);
+        }
+        Collections.reverse(al);
+        return al;
+    }
+
+}
+
+public class revLevelOrder {
+    public static void main(String[] args) {
+    BST_REV obj = new BST_REV();
+    obj.addNode(9);
+    obj.addNode(6);
+    obj.addNode(13);
+    obj.addNode(5);
+    obj.addNode(7);
+    obj.addNode(11);
+        System.out.println("Level order Traversal of the entered tree is: "+obj.levelOrder());
+        System.out.println("Reverse Level order of the tree is: "+obj.revLevelOrder());
+    }
+}