LeetCode 684: Redundant Connection With Union-Find
Subtitle / Summary The key signal in this problem is not a component count. It is a failed union: if two endpoints are already connected, adding the current edge closes a cycle. Reading time: 8-10 min Tags: Union-Find, DSU, graph, tree, cycle detection SEO keywords: LeetCode 684, Redundant Connection, Union-Find, DSU, cycle detection Meta description: A pressure-first Python guide to LeetCode 684 that derives 1-indexed Union-Find, bool-returning union, ordered edge scanning, and final checks. Problem Requirement You are given an undirected graph. It started as a tree with n nodes labeled from 1 to n, then one extra edge was added. ...