关于Kruskal最小生成树（MST）中某段代码的作用及执行时机的疑问

Hi everyone,

I'm currently diving into Kruskal's Minimum Spanning Tree (MST) — this classic greedy algorithm makes logical sense to me, and I can follow most of its implementation code from the tutorials I’ve worked through so far.

But I’ve hit a roadblock with one specific chunk of code: I can’t wrap my head around how it fits into the overall algorithm workflow. I’m hoping someone can break down when exactly this code gets triggered during program execution and explain the role of each relevant line.

内容的提问来源于stack exchange，提问作者Lama III