1 Problem 1 : The Number of Seniors and Juniors to Join the Company (https://leetcode.com/problems/the-number-of-seniors-and-juniors-to-join-the-company/)
2 Problem 2 : League Statistics (https://leetcode.com/problems/league-statistics/ )
3 Problem 3 : Sales Person (https://leetcode.com/problems/sales-person/ )
4 Problem 4 : Friend Requests II (https://leetcode.com/problems/friend-requests-ii-who-has-the-most-friends/ )