

Data Structures for Disjoint Sets - swannodette
http://compgeom.cs.uiuc.edu/~jeffe/teaching/algorithms/notes/16-unionfind.pdf

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chalst
I encountered this data structure over 20 years ago as an undergraduate, but
didn't recognise that it was the same structure used in Kruskal's algorithm
until I read this.

The time complexity of the path-compressed algorithm is very nice.

