Roadmap › Stage 7: Heaps & Backtracking › Pattern 32 of 53
DSA pattern guide

Heap — Sliding & Design

Scheduling with cooldowns, rearranging so neighbours differ, median of a stream.

Stage 7 · Heaps & Backtracking4 problems2 Medium · 2 Hard

Use it when

Scheduling with cooldowns, rearranging so neighbours differ, median of a stream.

Key idea

Always take the most urgent or frequent item from a heap. Two heaps (low/high) keep the median.

Practice problems, in order

  1. Task SchedulerMedium
  2. Reorganize StringMedium
  3. Sliding Window MaximumHard
  4. Sliding Window MedianHard

How to practise this pattern

  1. Read the problem and look for the signal above before writing any code.
  2. Say the brute force out loud, with its time complexity, then ask what work it repeats.
  3. Apply the key idea and write the optimised version yourself.
  4. If you're stuck for more than 10 minutes, take one small hint, not the full solution.
  5. Move to the next problem only when you can explain why this pattern fits.

Stuck on one of these?

The AlgoSolveo extension (free, launching soon) sits beside the LeetCode problem and gives the smallest hint that gets you moving, never the full answer. Solved problems tick off on your roadmap.

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