SDE - 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 have been given an integer array/list (ARR) of size N. You have to return an array/list PRODUCT such that PRODUCT[i] is equal to the product of all the elements of ARR except ARR[i]

 Note :

Each product can cross the integer limits, so we should take modulo of the operation. 

Take MOD = 10^9 + 7 to always stay in the limits.

Follow up :

Can you try solving the problem in O(1) space?

You are given two sorted linked lists. You have to merge them to produce a combined sorted linked list. You need to return the head of the final linked list.

Note:

The given linked lists may or may not be null.

For example:

If the first list is: 1 -> 4 -> 5 -> NULL and the second list is: 2 -> 3 -> 5 -> NULL

The final list would be: 1 -> 2 -> 3 -> 4 -> 5 -> 5 -> NULL

You are given a network with ‘N’ system nodes [0 to N - 1] and ‘M’ connection. Your task is to find out all critical connections in a given network.

Note: A connection between node ‘u’ and ‘v’ is said to be a critical connection, if after removal of a connection ‘u’ - ‘v’, there is no connection between node ‘u’ and ‘v’ and the network goes down.

For example:

For given N = 4, M = 4, 

The connection between system node 0 and 1 is a critical connection.

You are given D dice, each having F faces numbered 1 to F, both inclusive. The task is to find the possible number of ways to roll the dice together such that the sum of face-up numbers equal the given target S.

Note :

As the answer can be large, return your answer modulo 10^9  + 7.

Follow Up :

Can you solve this using not more than O(S) extra space?