type Stack[T any] struct {
    items []T
}

func (s *Stack[T]) Push(v T) { s.items = append(s.items, v) }

func (s *Stack[T]) Pop() (T, bool) {
    var zero T
    if len(s.items) == 0 {
        return zero, false
    }
    n := len(s.items) - 1
    v := s.items[n]
    s.items = s.items[:n]
    return v, true
}