package Trees;

public class valid_BST {

public static void main(String[] args) {

}

static class Node{

Node left,right;

public int data;

Node(int data){

this.data = data;

this.left = left;

this.right = right;

}

}

public boolean isValidBST(Node root){

return validate(root, null ,null);

}

public boolean validate(Node root, Integer max, Integer min){

if (root == null)

return true;

else if (max!= null && root.data>=max || min!=null && root.data < min) {

return false;

}else {

return validate(root.left,root.data,min)&&validate(root.right,max,root.data);

}

}

}