Implement Stack or Queue | Dataford Interview Questions

Implement a stack or a queue (It can be done using an array or a linked list).

Choose a stack implementation and process a sequence of operations, ensuring push, pop, peek, and size each run in O(1) time. The input is an array of operation arrays, and the output contains results for every non-push operation, with null returned for pop or peek on an empty stack. For example, [["push", 4], ["push", 9], ["pop"], ["size"]] returns [9, 1]; 1 <= operations.length <= 10^5, and pushed values are integers.

Constraints

1 <= operations.length <= 10^5
Each operation is one of ["push", value], ["pop"], ["peek"], or ["size"]
Values supplied to push are integers
Pop and peek on an empty stack return null

Function Signature

def process_stack(operations):

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Problem

Implement a stack or a queue (It can be done using an array or a linked list).

Constraints

1 <= operations.length <= 10^5
Each operation is one of ["push", value], ["pop"], ["peek"], or ["size"]
Values supplied to push are integers
Pop and peek on an empty stack return null

Function Signature

def process_stack(operations):

Your question is Implement Stack or Queue. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.