## Set.discard(), remove() & pop() Python

.remove(x) This operation removes element x from the set. If element x does not exist, it raises a KeyError. The .remove(x) operation returns None. Example: >>> s = set([1, 2, 3, 4, 5, 6, 7, 8, 9]) >>> s.remove(5) >>> print s set([1, 2, 3, 4, 6, 7, 8, 9]) >>> print s.remove(4) None >>> print s set([1, 2, 3, 6, 7, 8, 9]) >>> s.remove(0) KeyError: 0 .discard(x) This operation also removes element x from the set. If element x does not exist, it does not raise a KeyError. T

## Covariant Return Types

Java allows for Covariant Return Types, which means you can vary your return type as long you are returning a subclass of your specified return type. Method Overriding allows a subclass to override the behavior of an existing superclass method and specify a return type that is some subclass of the original return type. It is best practice to use the @Override annotation when overriding a superclass method. You will be given a partially completed code in the editor where the main method tak

## Bit Array

You are given four integers: N ,S ,P ,Q . You will use them in order to create the sequence a with the following pseudo-code. a[0] = S (modulo 2^31) for i = 1 to N-1 a[i] = a[i-1]*P+Q (modulo 2^31) Your task is to calculate the number of distinct integers in the sequence a. Input Format Four space separated integers on a single line N,S ,P and Q respectively. Output Format A single integer that denotes the number of distinct integers in the sequence a . Constraints

## Merge two sorted linked lists

This challenge is part of a tutorial track by MyCodeSchool Given pointers to the heads of two sorted linked lists, merge them into a single, sorted linked list. Either head pointer may be null meaning that the corresponding list is empty. Example headA refers to 1 -> 3 -> 7 -> NULL headB refers to 1 -> 2 -> NULL The new list is 1 -> 1 -> 2 -> 3 -> 7 -> NULL. Function Description Complete the mergeLists function in the editor below. mergeLists has the following parameters:

## Get Node Value

This challenge is part of a tutorial track by MyCodeSchool Given a pointer to the head of a linked list and a specific position, determine the data value at that position. Count backwards from the tail node. The tail is at postion 0, its parent is at 1 and so on. Example head refers to 3 -> 2 -> 1 -> 0 -> NULL positionFromTail = 2 Each of the data values matches its distance from the tail. The value 2 is at the desired position. Complete the getNode function in the editor below.