Randomly Shuffle a Deck | Dataford Interview Questions

Uline may use randomized card decks for testing warehouse picking workflows. Given a list representing a deck, return a uniformly random permutation of the cards without modifying the original list.

Implement shuffle_deck(deck, seed). The optional seed makes the result deterministic for testing. When seed is None, use system-provided randomness. Every permutation must have equal probability.

Formal Specification

Input: deck, a Python list containing distinct or repeated card values, and seed, an integer or None.
Output: A new Python list containing exactly the same values as deck, possibly in a different order.
The input list must remain unchanged.
Use the Fisher-Yates algorithm rather than repeatedly selecting and removing random elements.

Constraints

0 <= len(deck) <= 10^5
Card values may be any Python values that can be stored in a list
The input list must not be modified
The output must preserve every input value and its multiplicity

Function Signature

def shuffle_deck(deck, seed):

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