SDE - Intern

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?

Given a string 'S' of length 'L', return the length of the longest substring without repeating characters.

Example:

Suppose given input is "abacb", then the length of the longest substring without repeating characters will be 3 ("acb").

You are given an array ‘arr’ of ‘N’ distinct integers. Your task is to print all the non-empty subsets of the array.

Note: elements inside each subset should be sorted in increasing order. But you can print the subsets in any order, you don’t have to specifically sort them.

The node structure of a binary tree is modified such that each node has the reference to its parent node.

You are given two nodes: ‘N1’ and ‘N2’, of the above binary tree. Your task is to return the lowest common ancestor (LCA) of the given nodes.

Note:

Let ‘TREE’ be a binary tree. The lowest common ancestor of two nodes, ‘N1’ and ‘N2’, is defined as the lowest node in ‘TREE’ with ‘N1’ and ‘N2’ as descendants (where we allow a node to be a descendant of itself).

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