4 questions to do, given 90 minutes. Must complete at least 2 (but recommended to do as many as you can, if you only meet the minimum you might get wait listed)

Question 1:

- Simple max difference: Given an array return the max difference nums[j] - nums[i] for pairs nums[i] <= nums[j] where i < j. (I wasted a lot of time on this problem for some dumb incorrect if statement, think through your solution before solving this should be a quick 10 min problem)
- Ex. 7,2,3,10,1 the return value would be 10-2 and not 10-1 because 1 comes after the 10.

Question 2:

- Return number of subarrays that statisfy the condition given a number n where n is the amount of even numbers that may exist in the subarray and subarrays cannot end or start with same values (I skipped this one). Ex. 1,2,3,4,5 and n=2 you would return 4: [1,2,3], [1,2,3,4] [2,3,4,5] [3,4,5]

Question 3:

- Problem can be solved using Union find. Given array of edges calculate size of each tree take their square root if their size > 1 and add them up, if their size is 1 then just add 1. Return the sum.

Questiton 4:

- Simple DFS problem using stack https://leetcode.com/problems/keys-and-rooms/