SDE - 1

Given an integer ‘N’ representing the number of pairs of parentheses, Find all the possible combinations of balanced parentheses with the given number of pairs of parentheses.

Note :

Conditions for valid parentheses:
1. All open brackets must be closed by the closing brackets.

2. Open brackets must be closed in the correct order.

For Example :

()()()() is a valid parentheses.
)()()( is not a valid parentheses.

You are given a list of ‘N’ jobs which has to be performed. Each job is associated with a deadline and a profit if the job is completed before the deadline. Each job takes one unit of time to complete.

You are required to schedule the jobs in such a way that total profit will be maximized. Only one job can be scheduled at a time, and jobs can be scheduled at only integer moments of time greater than or equal to one.

For example-

Let there be three jobs ‘A’, ‘B’, and ‘C’-
•Profit and deadline associated with job ‘A’ being 20 and 1.
•Profit and deadline associated with job ‘B’ being 30 and 2.
•Profit and deadline associated with job ‘C’ being 40 and 2.

We will perform job ‘C’ at time t = 1 and job ‘B’ at time t = 2. The total profit will be 70. There is no other sequence of jobs which can fetch us a better overall profit. 

(100 Doors)

There are 100 doors in a row, all doors are initially closed. A person walks through all doors multiple times and toggle (if open then close, if close then open) them in the following way: 

In the first walk, the person toggles every door 

In the second walk, the person toggles every second door, i.e., 2nd, 4th, 6th, 8th, … 

In the third walk, the person toggles every third door, i.e. 3rd, 6th, 9th, … 

Likewise,
In the 100th walk, the person toggles the 100th door. 

Which doors are open in the end?
 

You are given an array 'a' of size 'n'.

Print the Next Greater Element(NGE) for every element.

The Next Greater Element for an element 'x' is the first element on the right side of 'x' in the array, which is greater than 'x'.

If no greater elements exist to the right of 'x', consider the next greater element as -1.

For example:

Input: 'a' = [7, 12, 1, 20]

Output: NGE = [12, 20, 20, -1]

Explanation: For the given array,

- The next greater element for 7 is 12.

- The next greater element for 12 is 20. 

- The next greater element for 1 is 20. 

- There is no greater element for 20 on the right side. So we consider NGE as -1.

You are given an array 'ARR' of 'N' integers and two integers 'K' and 'M'.

You need to return true if the given array can be divided into pairs such that the sum of every pair gives remainder 'M' when divided by 'K'. Otherwise, you need to return false.

For example:

If the given array is [2, 1, 5, 7] and K = 9 and M = 3. Then you need to return true because we can divide the array into two pairs, i.e (2, 1) and (5, 7) whose sums are 3 and 12, which when divided by 9 gives remainder 3, thus it is possible to divide the given array into pairs.  

Note:

Every element of the array should contribute to only one pair, i.e if the array is [3, 0, 0] and K = 2 and M = 1, then you need to return false, as element 3 will make a pair with any one of the 0. 

You are given a 2-dimensional array/list having N rows and M columns, which is filled with ones(1) and zeroes(0). 1 signifies land, and 0 signifies water.

A cell is said to be connected to another cell, if one cell lies immediately next to the other cell, in any of the eight directions (two vertical, two horizontal, and four diagonals).

A group of connected cells having value 1 is called an island. Your task is to find the number of such islands present in the matrix.

Given a directed graph, check whether the graph contains a cycle or not. Your function should return true if the given graph contains at least one cycle, else return false.