void solve(bfs_node nd)
{
while (q.Count >= 1 && !is_goal_done)
{
nd = q.Dequeue();
get_child(nd);
}
}
private bfs_node create_node(string state, bfs_node parent)
{
bfs_node nd = new bfs_node();
nd.state = state;
nd.parent = parent;
visited.add(state); q.Enqueue(nd);
return(nd);
}
public bfs(string state)
{
solution.Clear();
goal = get_goal(state.Length);
visited = new trie(state.Length);
bfs_node root = create_node(state, null);
solve(root);
}
void path(bfs_node nd)
{
bfs_node tmp = nd;
while (tmp != null)
{
solution.Push(tmp.state);
tmp = tmp.parent;
}
}
private void add(bfs_node parent, string c_state)
{
bfs_node ch_nd = create_node(c_state, parent);
is_goal_done = is_goal(c_state) ? true : false;
if (is_goal_done)
{
path(ch_nd);
}
}
void get_child(bfs_node nd)
{
if (is_goal_done)
{
return;
}
int idx = get_idx(nd.state), x = (int)Math.Sqrt(nd.state.Length);
if (idx >= x) // move top
{
string c_state = generate_state(nd.state, idx - x);
if (!visited.is_visited(c_state))
{
add(nd, c_state);
}
}
if (idx % x < x - 1 && !is_goal_done) // move right
{
string c_state = generate_state(nd.state, idx + 1);
if (!visited.is_visited(c_state))
{
add(nd, c_state);
}
}
if (idx < (x - 1) * x && !is_goal_done) // move down
{
string c_state = generate_state(nd.state, idx + x);
if (!visited.is_visited(c_state))
{
add(nd, c_state);
}
}
if (idx % x > 0 && !is_goal_done) // move left
{
string c_state = generate_state(nd.state, idx - 1);
if (!visited.is_visited(c_state))
{
add(nd, c_state);
}
}
}
