SDE - 1

'N' students are standing in a row. You are given the height of every student standing in the row. Your task is to find the longest strictly increasing subsequence of heights from the row such that the relative order of the students does not change.

A subsequence is a sequence that can be derived from another sequence by deleting zero or more elements without changing the order of the remaining elements.

You have been given the start and end times of 'N' intervals. Write a function to check if any two intervals overlap with each other.

Note :

If an interval ends at time T and another interval starts at the same time, they are not considered overlapping intervals.

SQL queries were asked

You are given a string ‘STR’ of size ‘N’ and an integer ‘M’ (the number of rows in the zig-zag pattern of ‘STR’). Your task is to return the string formed by concatenating all ‘M’ rows when string ‘STR’ is written in a row-wise zig-zag pattern.

Example:

N = 12, M = 3 and STR = ‘CODINGNINJAS’

There are three rows (‘M = 3’) in the zig-zag pattern. Row one contains ‘CNN’, row two contains ‘OIGIJS’, and row three contains ‘DNA’. After concatenating the three rows, we get the string ‘CNNOIGIJSDNA’. So, the answer is ‘CNNOIGIJSDNA’.

Note:

1. The string ‘STR’ consists of capital letters only (i.e., characters from ‘A-Z’).

You have been given a permutation of ‘N’ integers. A sequence of ‘N’ integers is called a permutation if it contains all integers from 1 to ‘N’ exactly once. Your task is to rearrange the numbers and generate the lexicographically next greater permutation.

To determine which of the two permutations is lexicographically smaller, we compare their first elements of both permutations. If they are equal — compare the second, and so on. If we have two permutations X and Y, then X is lexicographically smaller if X[i] < Y[i], where ‘i’ is the first index in which the permutations X and Y differ.

For example, [2, 1, 3, 4] is lexicographically smaller than [2, 1, 4, 3].

Given a string S, remove consecutive duplicates from it recursively.

You are given an input string 'S'. Your task is to find and return all possible permutations of the input string.

Note:

1. The input string may contain the same characters, so there will also be the same permutations.

2. The order of permutation does not matter.

Design an e-commerce website like Flipkart/Amazon

Questions about race condition, semaphore, mutex, etc.
Was asked to explain the Reader-Writer problem and write its code.
Also, was asked to explain the conflicts which can happen in this scenario