Day 358 #707

Good morning! Here's your coding interview problem for today.

This problem was asked by Dropbox.

Create a data structure that performs all the following operations in O(1) time:

• plus: Add a key with value 1. If the key already exists, increment its value by one.
• minus: Decrement the value of a key. If the key's value is currently 1, remove it.
• get_max: Return a key with the highest value.
• get_min: Return a key with the lowest value.