SDE - 1

You are given the first term (A), the common ratio (R) and an integer N. Your task is to find the Nth term of the GP series.

The general form of a GP(Geometric Progression) series is A, A(R), A(R^2), A*(R^3) and so on where A is the first term of GP series

Note :

As the answer can be large enough, return the answer modulo 10^9 + 7.

You have been given a linked list where each node has a single character. You have also been given a string 'STR'.

You have to remove all the occurrences of string STR from the linked list.

Note:

1. Start checking from the end of the linked list and not from the beginning. For example, if the linked list is ( a, b, a ,b, a)  and the string is equal to “aba” , then the answer should be (a b), not (b a).

2. After removing an occurrence check again for new formations.

For a given array with N elements, you need to find the length of the longest subsequence from the array such that all the elements of the subsequence are sorted in strictly increasing order.

Strictly Increasing Sequence is when each term in the sequence is larger than the preceding term.

For example:

[1, 2, 3, 4] is a strictly increasing array, while [2, 1, 4, 3] is not.

You are given two strings 'A' and 'B' of words. Your task is to find out the most frequent and lexicographically smallest word in string 'A', which is not present in string 'B'. If no such word is present in 'A', then return -1.

Note:

1. A word is a sequence of one or more lowercase characters.

2. Words are separated by a single whitespace character.

Example:

For the given string 'A' = “coding ninjas coding ninjas” and 'B' = “data structures and algorithms”, so both the word 'coding' and 'ninjas' are not present in string 'B' and occur two times each, but the word “coding” is lexicographically smaller than the word “ninjas”. So the answer is “coding”.

Given a number ‘N', the task is to find the total number of derangements of a set of ‘N’ elements.

A ‘Derangement’ is a permutation of 'N' elements, such that no element appears in its original position. For example, a derangement of {0, 1, 2, 3} is {2, 3, 1, 0}.

For example, 'N' = 2 , {0, 1} and {1, 0} are the only derangement therefore output will be 1.