[Solved] What is an effective way to modify the Command pattern to support both undo and redo operations? - Ans: Maintain two stacks: one for undo and one for redo commands | LLD

LLD - Design — Tic-Tac-Toe Game

What is an effective way to modify the Command pattern to support both undo and redo operations?

AUse a hashmap to map commands to their inverse operations

BStore all commands in a single queue and replay them for redo

CImplement redo by calling execute() on the last undone command without tracking history

DMaintain two stacks: one for undo and one for redo commands

Step-by-Step Solution

Solution:

Step 1: Understand undo/redo requirements
Undo reverses last command; redo reapplies commands undone.
Step 2: Analyze data structures
Two stacks allow pushing commands on execute and undo, and moving commands between stacks for redo.
Final Answer:
Maintain two stacks: one for undo and one for redo commands -> Option D
Quick Check:
Two stacks efficiently support undo/redo [OK]

Quick Trick: Two stacks enable undo and redo [OK]

Common Mistakes:

MISTAKES

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