SDE - 1

You are given an array/list ‘ARR’ of ‘N’ positive integers and an integer ‘K’. Your task is to check if there exists a subset in ‘ARR’ with a sum equal to ‘K’.

Note: Return true if there exists a subset with sum equal to ‘K’. Otherwise, return false.

For Example :

If ‘ARR’ is {1,2,3,4} and ‘K’ = 4, then there exists 2 subsets with sum = 4. These are {1,3} and {4}. Hence, return true.

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.

Reverse a given stack of 'N' integers using recursion. You are required to make changes in the input parameter itself.

Note: You are not allowed to use any extra space other than the internal stack space used due to recursion.

Example:

Input: [1,2,3,4,5] 
Output: [5,4,3,2,1]

Given a Binary Tree of 'N' number of total nodes, return the sequence of values of the leftmost and rightmost node at each level.

For example:

For the given binary tree: 

Output: 1 2 3 4 6 7 10

Explanation: The leftmost and rightmost node respectively of each level are
Level 0: 1(only one node is present at 0th level)
Level 1: 2 3
Level 2: 4 6
Level 3: 7 10

You are given ‘N’ integers in the form of an array ‘ARR’. Count the number of subarrays having their sum as 0.

For example :

Let ‘ARR’ be: [1, 4, -5]
The subarray [1, 4, -5] has a sum equal to 0. So the count is 1.