DS Algo Round

1. https://leetcode.com/problems/merge-intervals/
   Provided with an input slot of working hours (8am-5pm) and the meetings that occur in the day, return a list of free slots during the day. If slots overlap, consider the employee would attend both the meetings (merge overlapping intervals).
2. https://leetcode.com/problems/4sum/ -
   (Egde Cases) --> Handle duplicates and integer overflow upon addition of 2 integers.