LeetCode 1061: Lexicographically Smallest Equivalent String
A clear explanation of finding the lexicographically smallest equivalent string using Union-Find with canonical representatives.
Tag
Union-Find
21 notes
LeetCode 1020: Number of Enclaves
A clear explanation of counting land cells unreachable from the grid border using BFS from boundary land cells.
LeetCode 684: Redundant Connection
Find the extra edge in an undirected graph that creates a cycle using Union-Find.
LeetCode 399: Evaluate Division
A clear explanation of solving division equations using graph traversal and weighted edges.
LeetCode 323: Number of Connected Components in an Undirected Graph
A clear explanation of counting connected components using Union-Find and graph traversal.
LeetCode 305: Number of Islands II
A clear explanation of Number of Islands II using Union-Find to dynamically merge connected land cells.
LeetCode 959: Regions Cut By Slashes
A clear explanation of counting regions formed by slashes using union find over four triangles per cell.
LeetCode 952: Largest Component Size by Common Factor
A clear explanation of solving Largest Component Size by Common Factor using prime factorization and union find.
LeetCode 839: Similar String Groups
A clear explanation of the Similar String Groups problem using graph connectivity and union-find.
LeetCode 827: Making A Large Island
A clear explanation of the Making A Large Island problem using connected component labeling and island size lookup.
LeetCode 924: Minimize Malware Spread
A clear explanation of minimizing malware spread by analyzing connected components with Union Find.
LeetCode 990: Satisfiability of Equality Equations
A clear explanation of checking equality and inequality constraints using union-find.
LeetCode 947: Most Stones Removed with Same Row or Column
A clear explanation of solving Most Stones Removed with Same Row or Column using connected components and union-find.
LeetCode 803: Bricks Falling When Hit
A reverse simulation and union-find solution for counting how many bricks fall after each hit.
LeetCode 721: Accounts Merge
A clear explanation of merging accounts that share emails using union find and sorted email groups.
LeetCode 737: Sentence Similarity II
Check sentence similarity with transitive word relationships using union-find.
LeetCode 685: Redundant Connection II
Find the directed edge to remove so a graph becomes a rooted tree again, handling both cycles and nodes with two parents.
LeetCode 547: Number of Provinces
A clear explanation of counting connected components in an undirected graph represented by an adjacency matrix.
LeetCode 261: Graph Valid Tree
A clear explanation of the Graph Valid Tree problem using Union Find to detect cycles and verify connectivity.
LeetCode 130: Surrounded Regions
Capture surrounded O regions by marking border-connected O cells first, then flipping the remaining O cells.
2.5 Disjoint Set Union Variants
Union-find with path compression and union by rank, rollback, parity, weighted, offline, and concurrent DSU designs.