Avl Tree

AvlTree.java

@@ -0,0 +1,160 @@
+class Node
+{
+	Node left;
+	Node right;
+	int data;
+	int height;
+}
+class AvlTree
+{
+	Node root=null;
+	Node insertUtil(int data,Node cur)
+	{	
+
+
+		if(cur==null)
+		{
+			cur=new Node();
+			cur.data=data;
+
+		}
+		else if(cur.data>=data)
+		{
+			cur.left=insertUtil(data,cur.left);
+			// cur.left.height+=1;
+		}
+		else
+		{
+			cur.right=insertUtil(data,cur.right);
+			//cur.right.height+=1;
+		}
+		int hright=0;
+		int hleft=0;
+		if(cur.right!=null){hright=cur.right.height;}
+		if(cur.left!=null){hleft=cur.left.height;}
+		cur.height=Math.max(hright,hleft)+1;
+		if(hright==hleft || Math.abs(hright-hleft)==1) 
+		{  //System.out.println(cur.data);
+			return cur;
+		}
+
+		if(hleft>hright)
+		{	
+
+
+			if(cur.left.left!=null)
+			{
+				hleft=cur.left.left.height;
+
+			}
+			if(cur.left.right!=null)
+			{
+				hright=cur.left.right.height;
+
+			}
+			if(hleft>=hright)
+			{
+				return rightRotation(cur);
+
+			}
+			else
+			{
+
+				cur.left=leftRotation(cur.left);
+				return rightRotation(cur);
+
+			}
+
+
+		}
+		else
+		{
+
+			if(cur.right.left!=null)
+			{
+				hleft=cur.right.left.height;
+
+			}
+			if(cur.right.right!=null)
+			{
+				hright=cur.right.right.height;
+
+			}
+			if(hleft<=hright)
+			{
+				return leftRotation(cur);
+
+
+			}
+			else
+			{
+				cur.right=rightRotation(cur.right);
+				return leftRotation(cur);
+
+			}	
+
+		}
+
+
+	}
+	int height(Node cur)
+	{
+		if(cur==null){return 0;}
+		return cur.height;
+	}
+	Node leftRotation(Node x)
+	{
+		Node y = x.right; 
+        Node T2 = y.left; 
+
+        // Perform rotation 
+        y.left = x; 
+        x.right = T2; 
+
+        //  Update heights 
+        x.height = Math.max(height(x.left), height(x.right)) + 1; 
+        y.height = Math.max(height(y.left), height(y.right)) + 1; 
+
+        // Return new root 
+        return y;		
+	}
+	Node rightRotation(Node y)
+	{
+		 Node x = y.left; 
+        Node T2 = x.right; 
+
+        // Perform rotation 
+        x.right = y; 
+        y.left = T2; 
+
+        // Update heights 
+        y.height = Math.max(height(y.left), height(y.right)) + 1; 
+        x.height = Math.max(height(x.left), height(x.right)) + 1; 
+
+        // Return new root 
+        return x; 
+	}
+	void insert(int data){root=insertUtil(data,root);}
+	void print(Node cur)
+	{
+		if(cur==null){return;}
+		print(cur.left);
+		System.out.println(cur.data);
+		print(cur.right);
+	}
+
+
+	public static void main(String args[])
+	{
+		AvlTree tree=new AvlTree();
+		tree.insert(4);
+		tree.insert(6);
+		tree.insert(3);
+		tree.insert(8);
+		tree.insert(2);
+		tree.insert(1);
+		tree.print(tree.root);
+		System.out.println(tree.root.height);
+
+	}
+}