package two

type minPath []move

func newHeap() *minPath {
	return &minPath{}
}

func (h minPath) Len() int {
	return len(h)
}

func (h minPath) Less(i, j int) bool {
	return h[i].cost < h[j].cost
}

func (h minPath) Swap(i, j int) {
	h[i], h[j] = h[j], h[i]
}

func (h *minPath) Push(x interface{}) {
	*h = append(*h, x.(move))
}

func (h *minPath) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[:n-1]
	return x
}