SDE - 1

You are Harshad Mehta’s friend. He told you the price of a particular stock for the next ‘n’ days.

You are given an array ‘prices’ which such that ‘prices[i]’ denotes the price of the stock on the ith day.

You don't want to do more than 2 transactions. Find the maximum profit that you can earn from these transactions.

Note

1. Buying a stock and then selling it is called one transaction.

2. You are not allowed to do multiple transactions at the same time. This means you have to sell the stock before buying it again. 

Example:

Input: ‘n’ = 7, ‘prices’ = [3, 3, 5, 0, 3, 1, 4].

Output: 6

Explanation: 
The maximum profit can be earned by:
Transaction 1: Buying the stock on day 4 (price 0) and then selling it on day 5 (price 3). 
Transaction 2: Buying the stock on day 6 (price 1) and then selling it on day 6 (price 4).
Total profit earned will be (3 - 0) + ( 4 - 1) = 6. 

There is a Binary Search Tree (BST) consisting of ‘N’ nodes. Each node of this BST has some integer data.

You are given the root node of this BST, and an integer ‘X’. Return true if there is a node in BST having data equal to ‘X’, otherwise return false.

A binary search tree (BST) is a binary tree data structure that has the following properties:

1. The left subtree of a node contains only nodes with data less than the node’s data.

2. The right subtree of a node contains only nodes with data greater than the node’s data.

3. The left and right subtrees must also be binary search trees.

Note:

It is guaranteed that all nodes have distinct data.