Summer analyst

Approach 1 (Recursive) :

1) Compare the head of both linked lists.
2) Find the smaller node among the two head nodes. The current element will be the smaller node among two head nodes.
3) The rest elements of both lists will appear after that.
4) Now run a recursive function with parameters, the next node of the smaller element, and the other head.
5) The recursive function will return the next smaller element linked with rest of the sorted element. Now point the next of current element to that, i.e curr_ele->next=recursivefunction()
6) Handle some corner cases. 
6.1) If both the heads are NULL return null.
6.2) If one head is null return the other.

TC : O(N), where N=length of the Linked List
SC : O(N)


Approach 2 (Iterative) :

1) Traverse the list from start to end.
2) If the head node of second list lies in between two nodes of the first list, insert it there and make the next node of second list the head. Continue this until there is no node left in both lists, i.e. both the lists are traversed.
3) If the first list has reached end while traversing, point the next node to the head of second list.

Note: Compare both the lists where the list with a smaller head value is the first list.

TC : O(N), where N=length of the Linked List
SC : O(1)

You are given an integer array ‘ARR’. You have to find the length of the shortest contiguous subarray such that, if you sort this subarray in ascending order, then the whole array will be sorted in ascending order.
An array 'C' is a subarray of array 'D' if it can be obtained by deletion of several elements(possibly zero) from the beginning and the end from array 'D'.

You are given an integer 'N'. Your task is to find the number formed after swapping each even bit of 'N' in its binary representation with its adjacent bit on the right, assuming that the least significant bit is an odd bit.

Aahad and Harshit always have fun by solving problems. Harshit took a sorted array consisting of distinct integers and rotated it clockwise by an unknown amount. For example, he took a sorted array = [1, 2, 3, 4, 5] and if he rotates it by 2, then the array becomes: [4, 5, 1, 2, 3].
After rotating a sorted array, Aahad needs to answer Q queries asked by Harshit, each of them is described by one integer Q[i]. which Harshit wanted him to search in the array. For each query, if he found it, he had to shout the index of the number, otherwise, he had to shout -1.
For each query, you have to complete the given method where 'key' denotes Q[i]. If the key exists in the array, return the index of the 'key', otherwise, return -1.