import std.conv, std.exception, std.stdio, std.typecons;

alias Tuple!(uint, "id") Link;

struct Node
{
	uint id;
	Link[] links;

	void addLink(uint l)
	{
		links ~= Link(l);
	}

	immutable(Node) idup() pure const @property
	{
		auto linkCopy = to!(Link[])(links);
		immutable ilinks = assumeUnique(linkCopy);
		return immutable(Node)(id, ilinks);
	}
}

struct Network
{
	Node[uint] nodes;

	void add(uint i, uint j)
	{
		if((i in nodes) is null)
			nodes[i] = Node(i);
		if((j in nodes) is null)
			nodes[j] = Node(j);

		nodes[i].addLink(j);
		nodes[j].addLink(i);
	}

	// Won't compile
	immutable(Network) idup() pure const @property
	{
		auto nodeCopy = to!(Node[uint])(nodes);
		immutable imnodes = assumeUnique(nodeCopy);
		return immutable(Network)(imnodes);
	}

	void print()
	{
		foreach(k; nodes.keys)
		{
			write("[", k, "]");
			foreach(l; nodes[k].links)
				write(" ", l.id);
			writeln();
		}
		writeln();
	}
}


void main()
{
	auto n1 = Node(1);

	n1.addLink(5);
	n1.addLink(6);
	writeln(n1.links);

	immutable n2 = n1.idup;
	writeln(n2.links);

	Network net1;
	net1.add(1, 7);
	net1.add(1, 8);
	net1.add(2, 9);
	net1.print();
}