math bit Pattern
13 problems
Pattern pages help build reusable solving frames. Identify signals first, then explain state, transition, and edge handling.
Recognition Signals
- They expect you to replace repeated subtraction with doubling or left shifts, not brute force loops.
- They are checking whether you know why INT_MIN cannot be safely negated in 32-bit signed arithmetic.
- Clarifies whether negative numbers and zero should return false.
Solve Flow
- 1. Define the active state/window.
- 2. Update state while preserving invariants.
- 3. Validate with edge-heavy examples.
Common Misses
- Taking abs(INT_MIN) in a 32-bit type and silently overflowing before the real logic even starts.
- Not handling zero and negative inputs correctly, returning true incorrectly.
- Checking only n > 0 or n & (n - 1) without verifying bit position can misidentify powers of two as powers of four.
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