BST6.java

public class BST6 {

    static class Node {

        int data;
        Node left;
        Node right;

        Node(int data) {
            this.data = data;
            this.left = null;
            this.right = null;
        }
    }

    static void Inorder(Node root) {
        if (root == null) {
            return;
        }
        Inorder(root.left);
        System.out.print(root.data + " ");
        Inorder(root.right);
    }

    static boolean isValidate(Node root, Node min, Node max) {
        if (root == null) {
            return true;
        }
        if (min != null && root.data <= min.data) {
            return false;
        } else if (max != null && root.data >= max.data) {
            return false;
        }
        return isValidate(root.left, min, root) && isValidate(root.right, root, max);

    }

    public static void main(String[] args) {

        Node root = new Node(5);
        root.right = new Node(7);
        root.left = new Node(1);
        root.left.right = new Node(3);
        root.left.right.left = new Node(2);
        root.left.right.right = new Node(4);

        Inorder(root);
        System.out.println();

        System.out.println(isValidate(root, null, null));

    }
}