// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package a

type Stack[E any] []E

func (s *Stack[E]) Push(e E) {
	*s = append(*s, e)
}

func (s *Stack[E]) Pop() (E, bool) {
	l := len(*s)
	if l == 0 {
		var zero E
		return zero, false
	}
	r := (*s)[l - 1]
	*s = (*s)[:l - 1]
	return r, true
}

func (s *Stack[E]) IsEmpty() bool {
	return len(*s) == 0
}

func (s *Stack[E]) Len() int {
	return len(*s)
}