SDE - 1

You are given an array 'ARR' of Integers having 'N' elements. The array contains an encoded message. For each index 'i', 'ARR[i]' denotes the frequency of the 'i'th' character in the message. The characters are of an alien language having 'N' alphabets. Given the frequency of each of the 'N' alphabets in the message, your task is to find out the Huffman codes for each of the 'N' alphabets in the message.

The Huffman Code for a message is the set of codes such that :

1) All codes are binary strings.
2) Each code should be able to determine its corresponding character uniquely.
3) The total numbers of bits used to represent the message are minimized.

Note:

If there are multiple sets of valid Huffman codes for a message. You can print any of them.

For example:

Consider the array ARR = [ 1, 4, 2 ] having 3 elements. 
The array containing Huffman Codes for the above array will be [ '10', '0', '11' ]. Other Valid Huffman Codes are [ '01', '1', '00' ], [ '00', '1', '01' ] etc. Codes like [ '1', '0', '01' ], [ '1', '10' , '0' ] are some of the invalid Huffman Codes.

You are given a 2-dimensional array/list having N rows and M columns, which is filled with ones(1) and zeroes(0). 1 signifies land, and 0 signifies water.

A cell is said to be connected to another cell, if one cell lies immediately next to the other cell, in any of the eight directions (two vertical, two horizontal, and four diagonals).

A group of connected cells having value 1 is called an island. Your task is to find the number of such islands present in the matrix.

You are given an array/list ARR consisting of N integers. Your task is to find all the distinct triplets present in the array which adds up to a given number K.

An array is said to have a triplet {ARR[i], ARR[j], ARR[k]} with sum = 'K' if there exists three indices i, j and k such that i!=j, j!=k and i!=j and ARR[i] + ARR[j] + ARR[k] = 'K'.

Note:

1. You can return the list of values in any order. For example, if a valid triplet is {1, 2, -3}, then {2, -3, 1}, {-3, 2, 1} etc is also valid triplet. Also, the ordering of different triplets can be random i.e if there are more than one valid triplets, you can return them in any order.
2. The elements in the array need not be distinct.
3. If no such triplet is present in the array, then return an empty list, and the output printed for such a test case will be "-1".