core :: DisjointSetNode :: defaultinit
# A node in the hierarchical representation of subsets
private class DisjointSetNode
# If parent == self then the node is a root
var parent: DisjointSetNode = self
# The rank to keep the structure balanced.
# The term rank is used instead of depth since
# path compression is used, see `DisjointSet::nfind`
var rank = 0
end
lib/core/collection/union_find.nit:235,1--244,3