Min Stack

Statement#

Design a custom stack class, Min Stack, allowing us to push, pop, and retrieve the minimum value in constant time. Implement the following methods for Min Stack:

• Constructor: This initializes the Min Stack object.

• Pop(): This removes and returns from the stack the value that was most recently pushed onto it.

• Push(): This pushes the provided value onto the stack.

• Min Number(): This returns the minimum value in the stack in $O(1)$ time.

Note: The time complexity of all the methods above should be $O(1)$.

Constraints:

• $-10^{4} \leq$ value $\leq 10^{4}$

• The Pop() and Min Number() methods will always be called on non-empty stacks.

• At most, $10^3$ calls will be made to Push(), Pop(), and Min Number().

Examples#

Understand the problem#

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

Figure it out!#

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Note: These building blocks relate to the scenario of pushing, popping, and retrieving the minimum value from the stack.

Try it yourself#

Implement your solution in min_stack.py in the following coding playground. You will need the provided supporting code to implement your solution.