NSUserDefaults, which is now called UserDefaults in Swift, is a mechanism for storing small pieces of data persistently across app launches. It’s typically used for storing user preferences, settings, and other simple data. The reason why UserDefaults can only store class instances and not other types directly is due to its design. UserDefaults is primarily …
SOLID represents 5 five design principles intended to make object-oriented designs more understandable, flexible, and maintainable. Let’s discuss one by one 1. Single Responsibility Principle Every class should have only one responsibilityExample: In below example class UserProfileManager is single responsibility class which has getUserProfile function 2.Open/Closed Principle Software entities such as classes, modules, and functions should be open for …
[Question]: Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.Example: – n = 2. — [“(())”, “()()”] Approach: We can solve using backtracking / recursion
[Question]: Given a positive integer number N. The task is to generate all the binary strings of N bits. These binary strings should be in ascending order.Example: – Input: 2Output:0 00 11 01 1
[Question]: Given an integer array nums and an integer k, remove all occurrences of k in nums in-place. The order of the elements may be changed. Then return the count after removal Approach: We can declare a variable which holds index initial it’s 0 now move elements which are not matched with k
[Question] Write a program to reverse a stack using recursion.Input: elements present in stack from top to bottom 1 2 3 4 Output: 4 3 2 1
[Question]: Given a stack, the task is to sort it using recursion.Input: elements present in stack from top to bottom -3 14 18 -5 30Output: 30 18 14 -3 -5Explanation: The given stack is sorted know 30 > 18 > 14 > -3 > -5
[Question]: Given a string s, find the length of the longest substring without repeating characters. Example 1: Input: s = “abcabxy” Output: 5 Explanation: The answer is “abcxy”, with the length of 5
[Question]: Given a linked list where every node represents a linked list and contains two pointers of its type: Condition: All linked lists are sorted and the resultant linked list should also be sorted
[Question]: Given the head of a linked list, rotate the list to the right by k places.Example: – Input: head = [1,2,3,4,5], k = 2 Output: [4,5,1,2,3] #Approach Step: 1 Create tail node which moves till endsStep: 2 Create curr the tail node is the (len-k)-th node (1st node is head)Step: 3 Reorder linked list
