SDE - 1

You have been given an array/list 'PREORDER' representing the preorder traversal of a BST with 'N' nodes. All the elements in the given array have distinct values.
Your task is to construct a binary search tree that matches the given preorder traversal.
A binary search tree (BST) is a binary tree data structure that has the following properties:
• The left subtree of a node contains only nodes with data less than the node’s data.
• The right subtree of a node contains only nodes with data greater than the node’s data.
• Both the left and right subtrees must also be binary search trees.

Step 1 : First I converted the number into string and checked if each character is 0 or 1
Step 2 : The interviewer asked me if there is any other approach to solve this problem
Step 3 : I picked the approach of picking up the digit of integer from last and then checking whether that it is 0 or 1

Step 4 : If we get a digit other than 0/1 we will break the loop. The interviewer was happy with this approach.

You are given an array/list 'NUM' of integers. You are supposed to rearrange the elements of the given 'NUM' so that after rearranging the given array/list there are no two adjacent elements present in the rearranged 'NUM' which will be the same.
For Example:
Input: NUM[] = {1,1,1,2,2,2} 
Output: {1,2,1,2,1,2}
Note: {2,1,2,1,2,1} is also valid because there are no two adjacent which are the same.

Tip 1 : Practice preorder, postorder and inorder traversal questions of a tree
Tip 2 : Understand merge sort
Tip 3 : Have complete understanding of Radix sort