Java Developer

• Which of the following is the brain of the computer? (Learn)
• Which of the following is a technique that marked the beginning of computer communication?

You are given a string 'str' of length 'N'.

Your task is to reverse the original string word by word.

There can be multiple spaces between two words and there can be leading or trailing spaces but in the output reversed string you need to put a single space between two words, and your reversed string should not contain leading or trailing spaces.

Example :

If the given input string is "Welcome to Coding Ninjas", then you should return "Ninjas Coding to Welcome" as the reversed string has only a single space between two words and there is no leading or trailing space.

You are given an undirected graph with N nodes in the form of an adjacency matrix. You are also given an integer M.

Your task is to find if you can color the vertices of the graph using at most M colors such that no two adjacent vertices are of the same color.

For example:

If the given adjacency matrix is:
[0 1 0]
[1 0 1]
[0 1 0] and M = 3.

The given adjacency matrix tells us that node 1 is connected to node 2 and node 2 is connected to node 3. 

So if we color vertex 1 with ‘red’, vertex 2 with ‘blue’, and vertex 3 with ‘red’, it is possible to color the given graph with two colors which is less than or equal to M.

Given a singly linked list of 'N' nodes. The objective is to determine the middle node of a singly linked list. However, if the list has an even number of nodes, we return the second middle node.

Note:

1. If the list is empty, the function immediately returns None because there is no middle node to find.
2. If the list has only one node, then the only node in the list is trivially the middle node, and the function returns that node.

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.

Note:

Can you solve each query in O(logN) ?