SDE - 1

Given a singly linked list of integers. Your task is to return the head of the reversed linked list.

For example:

The given linked list is 1 -> 2 -> 3 -> 4-> NULL. Then the reverse linked list is 4 -> 3 -> 2 -> 1 -> NULL and the head of the reversed linked list will be 4.

Follow Up :

Can you solve this problem in O(N) time and O(1) space complexity?

You are given an array 'ARR' of 'N' positive integers. You need to find the length of the longest switching contiguous subarray.

An array is called Switching if all the elements at even indices are equal and all the elements at odd indices are also equal.

For Example :

If the given 'ARR' is [1, 4, 1, 4, 3, 2, 3, 0]. Then {1, 4, 1, 4}, {3, 2, 3}, {3, 0}, {0} are some of the switching subarrays. But {1, 4, 3}, {1, 4, 1, 4, 3, 2, 3} are not.

A thief is robbing a store and can carry a maximal weight of W into his knapsack. There are N items and the ith item weighs wi and is of value vi. Considering the constraints of the maximum weight that a knapsack can carry, you have to find and return the maximum value that a thief can generate by stealing items.

You have been given a Binary Tree of 'n' nodes, where the nodes have integer values

Print the left view of the binary tree.

Example :

If the input tree is as depicted in the picture: 

The Left View of the tree will be:  2 35 2 

You have been given a Singly Linked List of integers, determine if it forms a cycle or not. If there is a cycle, remove the cycle and return the list.

A cycle occurs when a node's ‘next’ points back to a previous node in the list.

Design chess board.