Software Engineer

You have been given two Strings “STR1” and “STR2” of characters. Your task is to find the length of the longest common subsequence.

A String ‘a’ is a subsequence of a String ‘b’ if ‘a’ can be obtained from ‘b’ by deletion of several (possibly, zero or all) characters. A common subsequence of two Strings is a subsequence that is common to both Strings.

Given a ‘N’ * ’M’ maze with obstacles, count and return the number of unique paths to reach the right-bottom cell from the top-left cell. A cell in the given maze has a value '-1' if it is a blockage or dead-end, else 0. From a given cell, we are allowed to move to cells (i+1, j) and (i, j+1) only. Since the answer can be large, print it modulo 10^9 + 7.

For Example :

Consider the maze below :
0 0 0 
0 -1 0 
0 0 0

There are two ways to reach the bottom left corner - 

(1, 1) -> (1, 2) -> (1, 3) -> (2, 3) -> (3, 3)
(1, 1) -> (2, 1) -> (3, 1) -> (3, 2) -> (3, 3)

Hence the answer for the above test case is 2.

For a given integer array/list 'ARR' of size 'N' containing all distinct values, find the total number of 'Inversions' that may exist.

An inversion is defined for a pair of integers in the array/list when the following two conditions are met.

A pair ('ARR[i]', 'ARR[j]') is said to be an inversion when:

1. 'ARR[i] > 'ARR[j]' 
2. 'i' < 'j'

Where 'i' and 'j' denote the indices ranging from [0, 'N').

You are given a number ‘N’ and a query ‘Q.’ If ‘Q’ is 1, then you have to return the sum of all integers from 1 to ‘N,’ else if ‘Q’ is equal to 2 then you have to return the product of all integers from 1 to ‘N.’ Since the product can be very large, return it modulo 10 ^ 9 + 7.

For example

Given ‘N’ = 4, ‘Q’ = 1. 
Then the answer is 10 because the sum of all integers between 1 and 4 are 1, 2, 3, and 4. Hence 1 + 2 + 3 + 4 is equal to 10.