node_for_302.cpp

#include <string>
#include <vector>
#include <algorithm>
#include <iostream>

using namespace std;

class Node
{
public:
	string state;
	string path;

	vector<Node> valid_children()
	{
		auto valid_children = vector<Node>{};
		if (is_possible_up())
			valid_children.push_back(up());
		if (is_possible_right())
			valid_children.push_back(right());
		if (is_possible_down())
			valid_children.push_back(down());
		if (is_possible_left())
			valid_children.push_back(left());
		return valid_children;
	}
private:

	bool is_possible_up()
	{
		return state.find('0') > 2;
	}
	bool is_possible_right()
	{
		return (state.find('0') % 3) != 2;
	}
	bool is_possible_down()
	{
		return state.find('0') < 6;
	}
	bool is_possible_left()
	{
		return (state.find('0') % 3) != 0;
	}

	Node up()
	{
		Node child = Node{ child.path + 'U',  child.state = state };
		std::swap(child.state[state.find('0') - 3], child.state[state.find('0')]);
		return child;
	}

	Node right()
	{
		Node child;
		child.path = path;
		child.path += 'R';
		child.state = state;
		std::swap(child.state[state.find('0') + 1], child.state[state.find('0')]);
		return child;
	}
	Node down()
	{
		Node child;

		child.path = path;
		child.path += 'D';
		child.state = state;
		std::swap(child.state[state.find('0') + 3], child.state[state.find('0')]);

		return child;
	}
	Node left()
	{
		Node child;

		child.path = path;
		child.path += 'L';
		child.state = state;
		std::swap(child.state[state.find('0') - 1], child.state[state.find('0')]);

		return child;
	}
};

int main() {
	auto initNode = Node{ "041526783" , "" };
	auto children = initNode.valid_children();
	for (auto child : children)
	{
		cout << child.path << endl;
	}

	system("pause");
}