Largest bst in a binary tree

#1

hii i understand the question but cant build function that will tell at which position the bst is largest please help me to build the function

#2

Approach
you have to call on both parts of tree (left subtree and right subtree)
and get back 2 main things

  1. is this subtree is BST?
  2. size of subtree in left or right part

and now to check current subtree is bst or not
you need 2 things

  1. upper bound of node value( means max value it should have)
  2. lower bound of node value (min value it should have)
    these 2 things are required because for a valid BST
    left part should contains element less than root node and right part should contains elements greater than root node

i recommend to write code at your own first
then you can also take reference or hint from here
Reference Code

#3

i made the approach but ek problem aa rahi hai random input ke liye work fine but when i go to submit the code 3 test case pass ho rahe hai last wala pass nahi ho raha .help me in finding out error please
code: https://ide.codingblocks.com/s/582589