AndrewSouthpaw / DisjointSets-CPP

Simple implementation of DisjointSets data structure in C++

DisjointSets-CPP

This is my first public contribution to GitHub! Comments on my implementation are very welcome. I still have much to learn in programming.

This file provides a basic disjoint-sets data structure (http://en.wikipedia.org/wiki/Disjoint-set_data_structure) in C++. It includes weighted union and path compression features, thus has a running-time on M union-find operations on N objects in O(N + Mlog*(N)) time.

If you want to use this data structure for a type that does not have a standard hash function defined, you can add this code:

#include <functional>  // might be necessary?
namespace std {
	namespace tr1 {
		template <>
		struct hash<Type>{
			public :
			size_t operator()(const Type &a ) const
			{
				return ###hash code goes here###;
			}
		};
	};
};

(Based on this reference: http://marknelson.us/2011/09/03/hash-functions-for-c-unordered-containers/)

This implementation uses <unordered_map>, standard in C++11. If your compiler complains, a likely fix is to change it to:

#include <tr1/unordered_map>

and append tr1:: before any instantiation of unordered_map.