AlgoSolveoRoadmap › Stage 8: Graphs › Pattern 39 of 53
DSA pattern guide
Graph — Union Find & MST
Dynamic connectivity, redundant edges, grouping, cheapest way to connect all.
Use it when
Dynamic connectivity, redundant edges, grouping, cheapest way to connect all.
Key idea
find with path compression plus union by rank. Kruskal sorts edges and joins sets that aren't yet connected.
Practice problems, in order
- Redundant ConnectionMedium
- Connecting Cities (Min Cost)Medium
- Accounts MergeMedium
- Number of Islands IIMedium
How to practise this pattern
- Read the problem and look for the signal above before writing any code.
- Say the brute force out loud, with its time complexity, then ask what work it repeats.
- Apply the key idea and write the optimised version yourself.
- If you're stuck for more than 10 minutes, take one small hint, not the full solution.
- 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.
Join the extension waitlistTrack it on the roadmap