array plus rolling hash Pattern
2 problems
Pattern pages help build reusable solving frames. Identify signals first, then explain state, transition, and edge handling.
Recognition Signals
- Looking for subarrays matching a sequence of relative comparisons, not exact values.
- Hinting to consider pattern length and efficient checking, possibly via rolling hash.
- Tests the candidate's ability to transform arrays efficiently.
Solve Flow
- 1. Define the active state/window.
- 2. Update state while preserving invariants.
- 3. Validate with edge-heavy examples.
Common Misses
- Forgetting that subarray length is pattern length plus one, leading to index errors.
- Incorrectly transforming the array `nums` into `nums2` based on relative comparisons.
Recommended Ladder
#TitleDifficultyCategory
3034
Number of Subarrays That Match a Pattern I
Count all subarrays in a given integer array that strictly follow a defined numeric pattern using rolling hash checks ef…
Medium
array
3036Number of Subarrays That Match a Pattern II
Count subarrays matching a pattern of relative values using array transformation and rolling hash techniques.
Hard
array