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Algorithms
6 min read
10 LeetCode Patterns That Cover 85% of Coding Interviews
Stop grinding 500 random problems. Master these core algorithmic patterns to quickly recognize optimal solutions under extreme interview pressure.
Elena Rostova
Principal AI Researcher • Published 2026-03-20
## Quality Over Quantity in Coding Interviews
Grinding hundreds of blind problems often leads to burnout and rote memorization that shatters when an interviewer introduces a slight twist. Instead, classify every problem into fundamental mental models.
### Top 4 Critical Patterns:
1. **Sliding Window:** For contiguous subarray or substring problems (e.g., longest substring without repeating characters, minimum window substring).
2. **Two Pointers (Fast & Slow):** Linked list cycle detection, palindrome verification, trapping rain water.
3. **Monotonic Stack:** Next greater element, largest rectangle in histogram.
4. **Topological Sort (Kahn's Algorithm / DFS):** Course schedules, build order dependencies.