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 a 2-D array 'MATRIX' of dimensions N x M, of integers. You need to return the spiral path of the matrix.

Example Of Spiral Path:

You are given three positive integers ‘A’, ‘B’, and ‘M’. Your task is to find out the result of ‘A^B’ mod ‘M’.

This task was too easy for Ninja, and being a top-class ninja, he likes to make things a little difficult in order to enjoy solving them. So he converted B into base 3 and is now trying to find the answer.

But it seems like he made the task a little too difficult for himself. Being a good friend of Ninja, can you help find him ‘A^B mod M’ when ‘A’, ‘M’ is given in base 10 and ‘B’ is in base 3?

You have been given two strings, 'str1' and 'str2'.

Your task is to return true if the given two strings are isomorphic to each other, else return false.

Note :

Two strings are isomorphic if a one-to-one mapping is possible for every character of the first string ‘str1’ to every character of the second string ‘str2’ while preserving the order of the characters.

All occurrences of every character in the first string ‘str1’ should map to the same character in the second string, ‘str2’.

For example :

If str1 = “aab” and str2 = “xxy” then the output will be 1. ‘a’ maps to ‘x’ and ‘b’ maps to ‘y’.

If str1 = “aab” and str2 = “xyz” then the output will be 0. There are two different characters in 'str1', while there are three different characters in 'str2'. So there won't be one to one mapping between 'str1' and 'str2'.