midStacks
Implement a Stack using two Queues.
Updated Apr 28, 2026
Short answer
By making either the push or pop operation expensive by shifting elements between queues.
Deep explanation
Intermediate stack problems often involve monotonic properties or expression conversion. By making either the push or pop operation expensive by shifting elements between queues.
Real-world example
Compiler syntax checking for code blocks.
Common mistakes
- Using a single variable for min-tracking instead of a stack (fails when min is popped).
Follow-up questions
- Time complexity of sorting a stack?