SDE - 1

You are given an integer 'N', your task is to generate all combinations of well-formed parenthesis having ‘N’ pairs.

A parenthesis is called well-formed if it is balanced i.e. each left parenthesis has a matching right parenthesis and the matched pairs are well nested.

For Example:

For ‘N’ = 3,
All possible combinations are: 
((()))
(()())
(())()
()(())
()()()

Kevin has ‘N’ coins. Each coin has a specific width and diameter. Kevin wants to build a tower using these coins such that each coin in the tower has strictly less width and diameter as compared to all coins placed below this coin.

You have to find the maximum height of the tower that Kevin can build by using these coins.

Note:

The height of the tower is calculated by adding the width of all the coins used in the formation of this tower.

You have to place ‘N’ billboards across a highway of ‘M’ kilometres. All the possible sites to place a billboard is given in the ‘billboards’ array. The revenue earned by placing a billboard is described by the ‘revenue’ array, billboard at ‘billboard[i]’ will earn the revenue equal to ‘revenue[i]’. There is a condition that no two billboards can be placed within ‘X’ kilometres of each other.

For Example :

You are given billboards = [2, 8, 9, 10, 15], revenue = [20, 50, 10, 30, 5], ‘M’ = ‘20’, ‘X’ = 5, here we can place the billboard at positions 2, 8, 15, which will give the profit as 20 + 50 + 5 = 75. Hence the answer is 75.

You are given a list of “N” strings A. Your task is to check whether you can form a given target string using a combination of one or more strings of A.

Note :

You can use any string of A multiple times.

Examples :

A =[“coding”, ”ninjas”, “is”, “awesome”]  target = “codingninjas”
Ans = true as we use “coding” and “ninjas” to form “codingninjas”

You have been given an integer array/list(ARR) of size 'N'. It only contains 0s, 1s and 2s. Write a solution to sort this array/list.

Note :

Try to solve the problem in 'Single Scan'. ' Single Scan' refers to iterating over the array/list just once or to put it in other words, you will be visiting each element in the array/list just once.

Given a singly linked list, you have to detect the loop and remove the loop from the linked list, if present. You have to make changes in the given linked list itself and return the updated linked list.

Expected Complexity: Try doing it in O(n) time complexity and O(1) space complexity. Here, n is the number of nodes in the linked list.