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Implement Queue using Two Stacks is a easy coding interview question covering stack, design — the kind asked at FAANG (Facebook/Meta, Apple, Amazon, Netflix, Google) and AI-first companies like Anthropic, OpenAI, and Nvidia.
Implement a first-in first-out (FIFO) queue using only two stacks. Support: - push(x): add to back - pop(): remove from front - peek(): view front - empty(): check if empty
The amortized time per operation must be O(1).
Explain why amortized O(1) holds even though individual pop() calls may be O(n).
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