SDE - Intern

Asked oops and threads

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 arbitrary binary tree with N nodes, whose nodes have their values in the range of integers. You are given two nodes x, y from the tree. You have to print the least common ancestor of these nodes.

Least common ancestor of two nodes x, y in a tree or directed acyclic graph is the lowest node that has both nodes x, y as its descendants.

For example look at the tree below, the LCA of node 1 and 5 is 3.

Note :

You have to return the deepest node which has both x, y as its descendants.
There may be cases where one of u or v is not present in the tree. In those cases, the reference provided to u or v will be NULL.

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