SDE - 2

You have been given a permutation of ‘N’ integers. A sequence of ‘N’ integers is called a permutation if it contains all integers from 1 to ‘N’ exactly once. Your task is to rearrange the numbers and generate the lexicographically next greater permutation.

To determine which of the two permutations is lexicographically smaller, we compare their first elements of both permutations. If they are equal — compare the second, and so on. If we have two permutations X and Y, then X is lexicographically smaller if X[i] < Y[i], where ‘i’ is the first index in which the permutations X and Y differ.

For example, [2, 1, 3, 4] is lexicographically smaller than [2, 1, 4, 3].

The interviewer asked about a project I had worked on in my previous company and then asked me to explain its high-level design. He also asked follow-up questions, including whether I used OAuth 2.0 and some Android fundamentals, since I was applying for an Android Developer role.

The interviewer asked about FCM (Firebase Cloud Messaging), how it works, and what is contained inside the google-services.json and service-account.json files. He also asked about the SMS Retriever API used to retrieve OTPs without the READ SMS permission.

Additionally, he asked about frameworks like Retrofit and Dagger.

A monkey is given ‘n’ piles of bananas, where the 'ith' pile has ‘a[i]’ bananas. An integer ‘h’ is also given, which denotes the time (in hours) in which all the bananas should be eaten.

Each hour, the monkey chooses a non-empty pile of bananas and eats ‘m’ bananas. If the pile contains less than ‘m’ bananas, then the monkey consumes all the bananas and won’t eat any more bananas in that hour.

Find the minimum number of bananas ‘m’ to eat per hour so that the monkey can eat all the bananas within ‘h’ hours.

Example:

Input: ‘n’ = 4, ‘a’ =  [3, 6, 2, 8] , ‘h’ = 7

Output: 3

Explanation: If ‘m’ = 3, then 
The time taken to empty the 1st pile is 1 hour.
The time taken to empty the 2nd pile is 2 hour.
The time taken to empty the 3rd pile is 1 hour.
The time taken to empty the 4th pile is 3 hour.
Therefore a total of 7 hours is taken. It can be shown that if the rate of eating bananas is reduced, they can’t be eaten in 7 hours.

You have been given a sorted array/list 'arr' consisting of ‘n’ elements. You are also given an integer ‘k’.

Now the array is rotated at some pivot point unknown to you.

For example, if 'arr' = [ 1, 3, 5, 7, 8], then after rotating 'arr' at index 3, the array will be 'arr' = [7, 8, 1, 3, 5].

Now, your task is to find the index at which ‘k’ is present in 'arr'.

Note :

1. If ‘k’ is not present in 'arr', then print -1.
2. There are no duplicate elements present in 'arr'. 
3. 'arr' can be rotated only in the right direction.

Example:

Input: 'arr' = [12, 15, 18, 2, 4] , 'k' = 2

Output: 3

Explanation:
If 'arr' = [12, 15, 18, 2, 4] and 'k' = 2, then the position at which 'k' is present in the array is 3 (0-indexed).

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.