SDE - 1

Given an infinite supply of Indian currency i.e. [1, 2, 5, 10, 20, 50, 100, 500, 1000] valued coins and an amount 'N'.

Find the minimum coins needed to make the sum equal to 'N'. You have to return the list containing the value of coins required in decreasing order.

For Example

For Amount = 70, the minimum number of coins required is 2 i.e an Rs. 50 coin and a Rs. 20 coin.

Note

It is always possible to find the minimum number of coins for the given amount. So, the answer will always exist.

You have been given the preorder and inorder traversal of a binary tree. Your task is to construct a binary tree using the given inorder and preorder traversals.

Note:

You may assume that duplicates do not exist in the given traversals.

For example :

For the preorder sequence = [1, 2, 4, 7, 3] and the inorder sequence = [4, 2, 7, 1, 3], we get the following binary tree.

You are given a binary search tree of integers with N nodes. You are also given references to two nodes 'P' and 'Q' from this BST.

Your task is to find the lowest common ancestor(LCA) of these two given nodes.

The lowest common ancestor for two nodes P and Q is defined as the lowest node that has both P and Q as descendants (where we allow a node to be a descendant of itself)

A binary search tree (BST) is a binary tree data structure which 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.

For example:

'P' = 1, 'Q' = 3
tree = 2 1 4 -1 -1 3 -1 -1 -1,

The BST corresponding will be- 

Here, we can clearly see that LCA of node 1 and node 3 is 2.

You have been given a long type array/list 'arr’ of size 'n’.

It represents an elevation map wherein 'arr[i]’ denotes the elevation of the 'ith' bar.

Print the total amount of rainwater that can be trapped in these elevations.

Note :

The width of each bar is the same and is equal to 1.

Example:

Input: ‘n’ = 6, ‘arr’ = [3, 0, 0, 2, 0, 4].

Output: 10

Explanation: Refer to the image for better comprehension:

Note :

You don't need to print anything. It has already been taken care of. Just implement the given function.