package q133

type Node struct {
	Val       int
	Neighbors []*Node
}

func cloneGraph(node *Node) *Node {
	if node == nil {
		return nil
	}
	seen := map[*Node]*Node{}

	queue := []*Node{node}
	for ; len(queue) > 0; queue = queue[1:] {
		cur := queue[0]
		if _, ok := seen[cur]; ok {
			continue
		}
		cloned := &Node{
			Val:       cur.Val,
			Neighbors: []*Node{},
		}
		seen[cur] = cloned
		for _, n := range cur.Neighbors {
			if nCloned, ok := seen[n]; ok {
				// Link
				cloned.Neighbors = append(cloned.Neighbors, nCloned)
				nCloned.Neighbors = append(nCloned.Neighbors, cloned)
			} else {
				// Add to queue
				queue = append(queue, n)
			}
		}
	}
	return seen[node]
}

var _ = cloneGraph