python Write the function isBST2(t) that receives a binary tree t and determines if t is a binary search tree. Your function shoul give the same results as the one in the previous question, but now you are not allowed to use extra storage (that is, you cannot extract the elements of the tree to a list). Your function must run in time O ( n ) (no credit will be given if it takes longer than that). Hint: use recursion; every recursive call should receive the root and the minimum and maximum key values that the root could have. For example, the.figure below shows in red the minimum and maximum valid values for every key based on its ancestors. If there is a key that is greater than its maximum valid value or smaller than its minimum valid value, then the tree is not a binary search tree. We can see that all keys in the tree are in their valid ranges, thus the tree is a binary search tree. Valid values for the root are in the range [-infinity, infinity], since it has no ancestors. Since the value at the root is 26 , then its left subtree can only have key values in the [- in finity, 26] range, while the right subtree can only have keys in the [ 26 , in finity ] range. If we replaced key 16 by 30 , the tree would no longer be a binary search tree, since 30 is not in the [ 2 , 26 ] range. Notice that we define the ranges based only on a node's ancestors. Valid values for the root are in the range [-infinity, in finity]. Since the value at the root is 26 , then the left subtree can only have key values in the [-in finity, 26] range, while the right subtree can only have keys in the [26, in finity] range. In general, if the valid key range for a node with key k is [ k min , k max ] , the resulting valid ranges for its subtress will be [ k min , k ] for the left subtree and [ k , k max ] for the right subtree..

1. python
Write the function isBST2(t) that receives a binary tree t and determines if t is a binary search
tree. Your function shoul give the same results as the one in the previous question, but now you
are not allowed to use extra storage (that is, you cannot extract the elements of the tree to a list).
Your function must run in time O ( n ) (no credit will be given if it takes longer than that). Hint:
use recursion; every recursive call should receive the root and the minimum and maximum key
values that the root could have. For example, the.figure below shows in red the minimum and
maximum valid values for every key based on its ancestors. If there is a key that is greater than
its maximum valid value or smaller than its minimum valid value, then the tree is not a binary
search tree. We can see that all keys in the tree are in their valid ranges, thus the tree is a binary
search tree. Valid values for the root are in the range [-infinity, infinity], since it has no
ancestors. Since the value at the root is 26 , then its left subtree can only have key values in the [-
in finity, 26] range, while the right subtree can only have keys in the [ 26 , in finity ] range. If we
replaced key 16 by 30 , the tree would no longer be a binary search tree, since 30 is not in the [ 2
, 26 ] range. Notice that we define the ranges based only on a node's ancestors. Valid values for
the root are in the range [-infinity, in finity]. Since the value at the root is 26 , then the left
subtree can only have key values in the [-in finity, 26] range, while the right subtree can only
have keys in the [26, in finity] range. In general, if the valid key range for a node with key k is [
k min , k max ] , the resulting valid ranges for its subtress will be [ k min , k ] for the left subtree
and [ k , k max ] for the right subtree.