SDE - 1

The new year is here, and the lockdown is also over. To celebrate your new year eve, you reach your friend's house. Your friend knows you love video games, so he made you a game as a present. In the game, you have ‘N’ enemies located at distinct positive integers points on the number line. You have an array ‘L’ of length ‘N’, where ‘L[i]’ represents the position of the ‘ith’ enemy.

You also have ‘K’ bombs each of power ‘R’. When you blast a bomb of power ‘R’ at position ‘i’, it will destroy everything within a range [i - R, i + R]. To win the game, you have to find the minimum value of ‘R’, such that it is possible to destroy every enemy. It is not necessary to use all ‘K’ bombs.

For example:

Let’s say the array ‘L’ = [1, 3, 4, 5] and 'K' = 2 then after bombing at position ‘2’ with a bomb of power ‘1’, enemies in the range [1, 3] will be destroyed. So the remaining enemy will be at position [4, 5]. These two can be bombed by placing another bomb at position '4'. Hence, the power is '1'.

We are suffering from the Second wave of Covid-19. The Government is trying to increase its vaccination drives. Ninja wants to help the Government to plan an effective method to help increase vaccination following safety measures. Time is running out. Can you help the nation?

You are given two positive integers: ‘n,’ ‘maxVaccines’ denoting the number of days for which this vaccination drive will go on and the total number of vaccines available for the drive, respectively. You have to find the number of vaccines administered each day. You are also given a number ‘dayNumber,’ and we are interested to know the maximum number of vaccines that can be administered on ‘dayNumber’ th day.

The rules of the vaccination drive :

1. There should be a positive number of vaccines administered each day during the vaccination drive.

2. The absolute difference between the number of vaccines in two consecutive days should not exceed 1.

3. The sum of all the elements of the vaccines array does not exceed maxVaccines, that is, you cannot administer more vaccines than what is provided to you.

4. Vaccines administered on ‘dayNumber’ th day should be maximized.

Given a string S containing digits from 2 to 9 inclusive. Your task is to find all possible letter combinations that the number could represent.

A mapping from Digits to Letters (just like in Nokia 1100) is shown below. Note that 1 does not map to any letter.

You are given a Singly Linked List of integers. You need to reverse the Linked List by changing the links between nodes.

Note :

You do not need to print anything, just return the head of the reversed linked list. 

Zomato order ETA design

You are given an array of n integers (a1, a2,....,an), you need to find if the array contains a pythagorean triplet or not.

An array is said to have a pythagorean triplet if there exists three integers x,y and z in the array such that x^2 + y^2 = z^2.

Note

1. The integers x,y and z might not be distinct , but they should be present at different locations in the array i.e if a[i] = x, a[j] = y and a[k] = z, then i,j and k should be pairwise distinct.
2. The integers a,b and c can be present in any order in the given array.

Explain when to use Redis and when to use Memcached.