Merge pull request #45 from mahesh-11102/master

Binary Search Tree in java

Author: SarthakKeshari

Data Structure/Trees/Binary Trees/BinarySearchTree.java

@@ -0,0 +1,77 @@
+// Question:
+// Write a Java program to identify the kth smallest element in the binary search tree where k =8.
+
+import java.util.*;
+import java.io.*;
+
+// initializing node class
+class Node {
+	int data;
+	Node left, right;
+	Node(int x) // Node contructor 
+	{
+		data = x;
+		left = right = null;
+	}
+}
+
+public class BinaryTree {
+	
+	static int count = 0;
+	// insertion of element using recursion
+	public static Node insert(Node root, int data)
+	{
+		if (root == null)
+			return new Node(data);
+		if (data < root.data) // if the data is less than node data go left
+			root.left = insert(root.left, data);
+		
+		else if (data > root.data)  // if data is greater than node data go right
+			root.right = insert(root.right, data);
+		
+		return root;
+	}
+	
+	public static Node kthSmallest(Node root, int k)
+	{
+		if (root == null)
+			return null;
+		Node left = kthSmallest(root.left, k); // at this line we go to leftmost node, so that  we can start counting nth smallest from thatnode (leftmost)
+	
+		if (left != null)
+			return left; 
+		count++;
+		
+		if (count == k) // if we find the element at k return k;
+			return root;
+	
+		return kthSmallest(root.right, k);
+	}
+	
+	public static void printKthSmallest(Node root, int k)
+	{
+		count = 0;
+		Node res = kthSmallest(root, k); // get the smallest element 
+		
+		if (res == null)
+			System.out.println("can't print as k is greater than nodes");
+		else
+			System.out.println(k+"-th Smallest Element is " + res.data);
+	}
+		
+	public static void main (String[] args) {
+		Scanner take = new Scanner(System.in);
+		Node root = null; // initialising root node
+		
+        	System.out.print("enter number of elements in the list: ");
+			int size = take.nextInt();
+	
+	        while(size-- !=0)
+			root = insert(root, take.nextInt());  // calling insert method to insert the element in the tree
+		System.out.print("enter k: ");
+		int k = take.nextInt();
+		printKthSmallest(root, k); //calling this function to find the kth smallest element
+		
+		
+	}
+}