Uniform Random Spanning Tree from Node Groups

Problem Overview

Given n groups of nodes (e.g., [[1], [2,3], [4,5,6]]), each group is internally connected. You must connect all groups into a single connected graph using exactly k-1 edges (where k is the number of groups — the minimum required). Each edge is formed by picking one node from each of…

• 2 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
• The rest of the problem statement — full requirements, constraints, and edge cases
• Approach and trade-offs — what passing candidates did, and the mistakes that sink people