Q4_5.java

public class Q4_5{
	public static void main(String[] args){
		TreeNode root1 = new TreeNode(7,new TreeNode(2,new TreeNode(1),new TreeNode(3,null,new TreeNode(8))),new TreeNode(11));
	    System.out.println(isBST(root1,Integer.MAX_VALUE,Integer.MIN_VALUE));
	}
	static boolean isBST(TreeNode root, int max, int min){
		if(root == null)
			return true;
		int value = (Integer) root.value;
		if(value>max || value<min)
			return false;
		if(!isBST(root.left,value,min))
			return false;
		if(!isBST(root.right,max,value))
			return false;
		return true;
	}
	
}