# DisjointSet

An implementation of the Disjoint-set data structure for Julia. This package is based on JuliaCollections's implementation of the Disjoint-set data structure in DataStructures.jl. However, this package uses union-by-size rather than union-by-rank, which allows one to find the size of any given set in near-constant time.

## Usage

s = IntDisjointSets(10) # creates a forest comprised of 10 singletons
union!(s, 3, 5) # merges the sets that contain 3 and 5 into one and returns the root of the new set
root_union!(s, x, y) # merges the sets that have root x and y into one and returns the root of the new set
# (assumes x != y)
find_root!(s, 3) # finds the root element of the subset that contains 3
in_same_set(s, x, y) # determines whether x and y are in the same set
num_sets(s) # returns the number of sets in s
set_size(s, x) # find the size of the set that x is in
elem = push!(s) # adds a single element in a new set; returns the new element
# (this operation is often called MakeSet)

One may also use other element types:

s = DisjointSets{AbstractString}(["a", "b", "c", "d"])
union!(s, "a", "b")
in_same_set(s, "c", "d")
push!(s, "f")

etc...