I was sent a HackerRank test via email and was given 90 minutes to complete it anytime within the week.

The first problem was not bad.

The next problem took most of my time, and I didn't finish it.

The last problem was probably the same difficulty as the second, but I had no time left.

Given a 2D array keystrokes:

• The first element is an integer representing an encoded letter (0 for 'a', 1 for 'b', etc.).
• The second element is an integer representing the time it took to press the key after the previous key.

Times are sorted in ascending order. Return the letter with the slowest time.

Given an array of weights and an integer for the maximum weight capacity, return the maximum amount of weight that can be made with the provided weights.

Given a 2D array of grid values for each row and a maximum value, find the maximum size square where the sum of the values is less than or equal to the maximum value. For example:

Given [[1, 1, 1], [2, 2, 2], [3, 3, 3]] and a maximum value of 27, what is the maximum size square?