Prompt

Implement a MinMaxStack class that works like a regular stack but also lets you retrieve the current minimum and maximum values at any time, without removing anything.

Your class should support:

• push(number) — adds a number to the top
• pop() — removes and returns the top number
• peek() — returns the top number without removing it
• isEmpty() — returns true if the stack is empty
• getMin() — returns the smallest number currently in the stack
• getMax() — returns the largest number currently in the stack

getMin() and getMax() must work in constant time (no looping through the whole stack).