Practical applications of disjoint set datastructure

I know that the disjoint set datastructure is used to keep track of the connected components of an undirected graph when the edges are added to the graph dynamically . I also know that is is used in Kruskal's algorithm for minimum spanning trees . What are the other possible applications of this datastructure ?

• Maze generation (using a modified Kruskal's algorithm)

• Tarjan's off-line least common ancestors algorithm

• Connected component labeling

• Online maintenance of biconnected components

• Validation Hindley–Milner rules

• Computing the winner of Havannah board game (see Efficient Playouts for the

Havannah Abstract Board Game)

• Alias analysis

• Used in construction of contour trees (see Laying the Foundations for an Advanced

Visualization System in O'Caml and Multi-Resolution computation and presentation of Contour Trees)

StackExchange Computer Science Q#6308, answer score: 7