How to check if a Queue is full or empty?

Updated Apr 28, 2026

Short answer

Empty when front -1; Full when (rear + 1) % size front.

Deep explanation

Mid-level queue concepts involve specific optimizations and algorithm integration. Empty when front -1; Full when (rear + 1) % size front.

Real-world example

Managing requests in a web server buffer.

Common mistakes

  • Forgetting to reset pointers to -1 when the last element is dequeued.

Follow-up questions

  • What is the time complexity of Heap-based PQ push?

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