SDE - 1

You are given some information about the rooms of a military camp. The rooms are numbered from 0 to 'N-1'. Each room contains keys to some other rooms. You can visit a room only if you have a key to that room. Your task is to determine whether each room can be visited or not.

Note:

1. Room 0 is the only room that is initially unlocked and doesn’t require any key to enter.

2. Any other room can be visited only if you have the key to that room.

3. More than one room can have keys to the same room.

4. You are allowed to visit rooms in any order.

5. You can visit any room multiple times.

Given a string "pattern", which contains only two types of characters ‘(’, ‘)’.

Your task is to find the minimum number of parentheses either ‘(’, ‘)’ we must add the parentheses in string ‘pattern’ and the resulted string is valid.

Condition for valid string-

Every opening parenthesis ‘(’ must have a correct closing parenthesis ‘)’.

Example - ‘(()(()))’, ‘()()()’, ‘((()))’ are valid string, and ‘(((’, ‘(()’, ‘)(())’ are invalid string.

Note:

1. You are not required to print the output explicitly, it has already been taken care of. Just implement the function and return the minimum number of parentheses required to make a string valid.

You are given an array/list ARR consisting of N integers. Your task is to find all the distinct triplets present in the array which adds up to a given number K.

An array is said to have a triplet {ARR[i], ARR[j], ARR[k]} with sum = 'K' if there exists three indices i, j and k such that i!=j, j!=k and i!=j and ARR[i] + ARR[j] + ARR[k] = 'K'.

Note:

1. You can return the list of values in any order. For example, if a valid triplet is {1, 2, -3}, then {2, -3, 1}, {-3, 2, 1} etc is also valid triplet. Also, the ordering of different triplets can be random i.e if there are more than one valid triplets, you can return them in any order.
2. The elements in the array need not be distinct.
3. If no such triplet is present in the array, then return an empty list, and the output printed for such a test case will be "-1".

Design and implement a data structure for Least Recently Used (LRU) cache to support the following operations:

1. get(key) - Return the value of the key if the key exists in the cache, otherwise return -1.

2. put(key, value), Insert the value in the cache if the key is not already present or update the value of the given key if the key is already present. When the cache reaches its capacity, it should invalidate the least recently used item before inserting the new item.

You will be given ‘Q’ queries. Each query will belong to one of these two types:

Type 0: for get(key) operation.
Type 1: for put(key, value) operation.

Note :

1. The cache is initialized with a capacity (the maximum number of unique keys it can hold at a time).

2. Access to an item or key is defined as a get or a put operation on the key. The least recently used key is the one with the oldest access time.

You are given an arbitrary linked list consisting of 'N' nodes having integer values. You need to perform insertion sort on the linked list and print the final list in sorted order.

In other words, you are given a singly linked list, you need to perform insertion sort on it.

Insertion Sort is a sorting algorithm that removes one element from the input data, finds the location it belongs within the sorted list and inserts it there. It repeats until no input elements remain.