SDE - 1

You have been given an array/list 'arr' consisting of 'n' elements.

Each element in the array is either 0, 1 or 2.

Sort this array/list in increasing order.

Do not make a new array/list. Make changes in the given array/list.

Example :

Input: 'arr' = [2, 2, 2, 2, 0, 0, 1, 0]

Output: Final 'arr' = [0, 0, 0, 1, 2, 2, 2, 2]

Explanation: The array is sorted in increasing order.

Given a graph with 'V' vertices numbered from 0 to 'V' - 1 and 'E' edges. Determine if it is a tree or not?

You are given string S of length N, and an integer K. Your task is to find the length of the longest substring that contains at most K distinct characters.

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.

Ninjas is practicing problems on the linked list. He came across a problem in which he has given a linked list of ‘N’ nodes and two integers, ‘LOW’ and ‘HIGH’. He has to return the linked list ‘HEAD’ after reversing the nodes between ‘LOW’ and ‘HIGH’, including the nodes at positions ‘LOW’ and ‘HIGH’.