SDE - 1

Given two strings, 'S' and 'T' with lengths 'M' and 'N', find the length of the 'Longest Common Subsequence'.

For a string 'str'(per se) of length K, the subsequences are the strings containing characters in the same relative order as they are present in 'str,' but not necessarily contiguous. Subsequences contain all the strings of length varying from 0 to K.

Example :

Subsequences of string "abc" are:  ""(empty string), a, b, c, ab, bc, ac, abc.

You are given a linked list of 'n' nodes and an integer 'k', where 'k' is less than or equal to 'n'.

Your task is to reverse the order of each group of 'k' consecutive nodes, if 'n' is not divisible by 'k', then the last group of nodes should remain unchanged.

For example, if the linked list is 1->2->3->4->5, and 'k' is 3, we have to reverse the first three elements, and leave the last two elements unchanged. Thus, the final linked list being 3->2->1->4->5.

Implement a function that performs this reversal, and returns the head of the modified linked list.

Example:

Input: 'list' = [1, 2, 3, 4], 'k' = 2

Output: 2 1 4 3

Explanation:
We have to reverse the given list 'k' at a time, which is 2 in this case. So we reverse the first 2 elements then the next 2 elements, giving us 2->1->4->3.

Note:

All the node values will be distinct.

Given a list of cities numbered from 0 to N-1 and a matrix 'DISTANCE' consisting of 'N' rows and 'N' columns denoting the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the starting city?

You are given a list/array of strings which denotes the contacts that exist in your phone directory. The search query on a string ‘str’ which is a query string displays all the contacts which are present in the given directory with the prefix as ‘str’. One special property of the search function is that when a user searches for a contact from the contact list then suggestions (contacts with prefix as the string entered so for) are shown after the user enters each character.

Note :

If no suggestions are found, return an empty 2D array.

For Example :

In the above example everytime we enter a character, a few suggestions display the strings which contain the entered string as prefixes.

There are 100 doors, all closed. 

In a nearby cage are 100 monkeys.

The first monkey is let out and runs along the doors opening every one. 

The second monkey is then let out and runs along the doors closing the 2nd, 4th, 6th,… - all the even-numbered doors. 

The third monkey is let out. He attends only to the 3rd, 6th, 9th,… doors (every third door, in other words), closing any that is open and opening any that is closed, and so on. 

After all 100 monkeys have done their work in this way, what state are the doors in after the last pass?