SDE - 1

You are given a list of a repeated set of integers. Your task for the problem is to return a list of the given elements in decreasing sorted order of their frequency of repetition in the given list with the element with the highest frequency of repetition first and so on.

Note :

If two numbers have the same frequency then keep the one that was present before the other in the original given list (array) first.

For Example :

Input:  arr[] = {2, 5, 2, 8, 5, 6, 8, 8}
Output: arr[] = {8, 8, 8, 2, 2, 5, 5, 6}

Explanation :
When you sort the array based on the decreasing order of the frequency of repetition of integers in the original array, 
you’ll find that the element ‘8’ is the integer with the most repeated values therefore it would be arranged first after which since both 2 and 5 have the same number of repeated 
values in the original array but since the 2 arrived first so we will first arrange 2 and then 5 in our resultant array, while would be the last element after sorting here.

You are given N number of intervals, where each interval contains two integers denoting the start time and the end time for the interval.

The task is to merge all the overlapping intervals and return the list of merged intervals sorted by increasing order of their start time.

Two intervals [A,B] and [C,D] are said to be overlapping with each other if there is at least one integer that is covered by both of them.

For example:

For the given 5 intervals - [1, 4], [3, 5], [6, 8], [10, 12], [8, 9].

Since intervals [1, 4] and [3, 5] overlap with each other, we will merge them into a single interval as [1, 5].

Similarly, [6, 8] and [8, 9] overlap, merge them into [6,9].

Interval [10, 12] does not overlap with any interval.

Final List after merging overlapping intervals: [1, 5], [6, 9], [10, 12].

What is overriding and overloading?

What are compile time and run time exceptions?

Given a singly linked list of integers. Your task is to return the head of the reversed linked list.

For example:

The given linked list is 1 -> 2 -> 3 -> 4-> NULL. Then the reverse linked list is 4 -> 3 -> 2 -> 1 -> NULL and the head of the reversed linked list will be 4.

Follow Up :

Can you solve this problem in O(N) time and O(1) space complexity?

Given a number of ropes say ‘N’ and an array of integers of size ‘N’ containing the length of ropes. Your task is to connect the ropes into one. The cost to connect two ropes is equal to the sum of their lengths. Find the minimum cost for connecting all the ropes.

Given an array arr of length N consisting of positive and negative integers, return the length of the longest subarray whose sum is zero.

You are given a singly linked list of integers.

Your task is to swap every two adjacent nodes, and return the head of the modified, linked list.

For Example:

We have a linked list 1->2->3->4->5->6->7 and so on. You are supposed to swap pairs of a linked list like swap (1,2), (3,4), (5,6), and so on.

Note:

1. You may not modify the data in the list’s nodes; only nodes themselves may be changed. Because imagine a case where a node contains many fields, so there will be too much unnecessary swap.

2. If a pair of a node does not exist, then leave the node as it is.

What is Js event loop?

What is the difference between synchronous and asynchronous in JS?