Implement a LIFO stack using only two queues. Support push, pop, top, and empty.
MyStack → push(1) → push(2) → top()→2 → pop()→2 → empty()→false
Unlock hints progressively — start gentle, go deeper only if needed.
Level 1: Gentle Nudge
A subtle direction
Level 2: Approach
The algorithm to use
Level 3: Detailed
Step-by-step guidance
to save progress and use AI features