MTS 1

Ninja has been given an array/list ‘ARR’ of even size ‘N’ and an integer ‘K’. Ninja gives his friend a task to divide the given ‘ARR’ into ‘N’/2 pairs such that the sum of each pair should be divisible by ‘K’.

Can you help Ninja to do this task?

For Example :

If ‘ARR’ = [4 5 6 5 7 3] and ‘K’ = 5
Pairs are(4, 6), (5, 5) ,and (7, 3) and the sum of elements of each pair is divisible by ‘K’ i.e 5.

You have been given a non-empty grid consisting of only 0s and 1s. You have to find the number of islands in the given grid.

An island is a group of 1s (representing land) connected horizontally, vertically or diagonally. You can assume that all four edges of the grid are surrounded by 0s (representing water).

You are given an array/list ‘ARR’ of ‘N’ integers. You have to generate an array/list containing squares of each number in ‘ARR’, sorted in increasing order.

For example :

Input:
‘ARR’ = [-6,-3, 2, 1, 5] 

If we take a square of each element then the array/list will become [36, 9, 4, 1, 25].
Then the sorted array/list will be [1, 4, 9, 25, 36].

Output :
[1, 4, 9, 25, 36].

Given a string input of length n, find the length of the longest substring without repeating characters i.e return a substring that does not have any repeating characters.

Substring is the continuous sub-part of the string formed by removing zero or more characters from both ends.

You have been given an array/list 'WORDS' of 'N' non-empty words, and an integer 'K'. Your task is to return the 'K' most frequent words sorted by their frequency from highest to lowest.

Note:

If two words have the same frequency then the lexicographically smallest word should come first in your answer.

Follow up:

Can you solve it in O(N * logK) time and O(N) extra space?