feat(stack): implement stack in golang code

codes/go/chapter_stack_and_queue/array_stack.go

@@ -0,0 +1,73 @@
+// File: array_stack.go
+// Created Time: 2022-11-26
+// Author: Reanon (793584285@qq.com)
+
+package chapter_stack_and_queue
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// ArrayStack 基于数组实现的栈
+type ArrayStack struct {
+	data []int // 数据
+}
+
+func NewArrayStack() *ArrayStack {
+	return &ArrayStack{
+		// 设置栈的长度为 0，容量为 16
+		data: make([]int, 0, 16),
+	}
+}
+
+// Size 栈的长度
+func (s *ArrayStack) Size() int {
+	return len(s.data)
+}
+
+// IsEmpty 栈是否为空
+func (s *ArrayStack) IsEmpty() bool {
+	return s.Size() == 0
+}
+
+// Push 入栈
+func (s *ArrayStack) Push(v int) {
+	// 切片会自动扩容
+	s.data = append(s.data, v)
+}
+
+func (s *ArrayStack) Pop() any {
+	// 弹出栈前，先判断是否为空
+	if s.IsEmpty() {
+		return nil
+	}
+	val := s.Peek()
+	s.data = s.data[:len(s.data)-1]
+	return val
+}
+
+func (s *ArrayStack) Peek() any {
+	if s.IsEmpty() {
+		return nil
+	}
+	val := s.data[len(s.data)-1]
+	return val
+}
+
+func (s *ArrayStack) Print() {
+	fmt.Println(s.toString())
+}
+
+func (s *ArrayStack) toString() string {
+	var builder strings.Builder
+	if s.IsEmpty() {
+		return "empty stack"
+	}
+	for i := len(s.data) - 1; i > 0; i-- {
+		builder.WriteString(strconv.Itoa(s.data[i]) + " -> ")
+	}
+	builder.WriteString(strconv.Itoa(s.data[0]))
+	return builder.String()
+}

codes/go/chapter_stack_and_queue/linkedlist_stack.go

@@ -0,0 +1,79 @@
+// File: linkedlist_stack.go
+// Created Time: 2022-11-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_stack_and_queue
+
+import (
+	"container/list"
+	"fmt"
+	"strings"
+)
+
+// LinkedListStack 基于链表实现的栈, 使用内置包 list 来实现栈
+type LinkedListStack struct {
+	list *list.List
+}
+
+// NewLinkedListStack 初始化链表
+func NewLinkedListStack() *LinkedListStack {
+	return &LinkedListStack{
+		list: list.New(),
+	}
+}
+
+// Push 入栈
+func (s *LinkedListStack) Push(value any) {
+	s.list.PushBack(value)
+}
+
+// Pop 出栈
+func (s *LinkedListStack) Pop() any {
+	if s.IsEmpty() {
+		return nil
+	}
+	e := s.list.Back()
+	s.list.Remove(e)
+	return e.Value
+}
+
+// Peek 访问栈顶元素
+func (s *LinkedListStack) Peek() any {
+	if s.IsEmpty() {
+		return nil
+	}
+	e := s.list.Back()
+	return e.Value
+}
+
+// Size 获取栈的长度
+func (s *LinkedListStack) Size() int {
+	return s.list.Len()
+}
+
+// IsEmpty 判断栈是否为空
+func (s *LinkedListStack) IsEmpty() bool {
+	return s.list.Len() == 0
+}
+
+func (s *LinkedListStack) Print() {
+	fmt.Println(s.toString())
+}
+
+func (s *LinkedListStack) toString() any {
+	var builder strings.Builder
+	if s.IsEmpty() {
+		fmt.Println("empty stack")
+		return nil
+	}
+	e := s.list.Back()
+	// 强转为 string, 会影响效率
+	str := fmt.Sprintf("%v", e.Value)
+	for e.Prev() != nil {
+		builder.WriteString(str + " -> ")
+		e = e.Prev()
+		str = fmt.Sprintf("%v", e.Value)
+	}
+	builder.WriteString(str)
+	return builder.String()
+}

codes/go/chapter_stack_and_queue/stack.go

@@ -0,0 +1,18 @@
+// File: stack.go
+// Created Time: 2022-11-26
+// Author: Reanon (793584285@qq.com)
+
+package chapter_stack_and_queue
+
+type Stack interface {
+	// Push 元素入栈
+	Push(num int)
+	// Peek 访问栈顶元素
+	Peek() int
+	// Pop 元素出栈
+	Pop() int
+	// Size 栈的长度
+	Size() int
+	// IsEmpty 栈是否为空
+	IsEmpty() bool
+}

codes/go/chapter_stack_and_queue/stack_test.go

@@ -0,0 +1,93 @@
+// File: stack_test.go
+// Created Time: 2022-11-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_stack_and_queue
+
+import "testing"
+
+func TestStack(t *testing.T) {
+	// 初始化栈
+	stack := NewLinkedListStack()
+
+	// 元素入栈
+	stack.Push(1)
+	stack.Push(2)
+	stack.Push(3)
+	stack.Push(4)
+	stack.Push(5)
+	t.Log("栈 stack = ", stack.toString())
+
+	// 访问栈顶元素
+	peek := stack.Peek()
+	t.Log("栈顶元素 peek = ", peek)
+
+	// 元素出栈
+	pop := stack.Pop()
+	t.Log("出栈元素 pop  = ", pop, ", 出栈后 stack =", stack.toString())
+
+	// 获取栈的长度
+	size := stack.Size()
+	t.Log("栈的长度 size = ", size)
+
+	// 判断是否为空
+	isEmpty := stack.IsEmpty()
+	t.Log("栈是否为空 = ", isEmpty)
+}
+
+func TestArrayStack(t *testing.T) {
+	// 初始化栈
+	stack := NewArrayStack()
+
+	// 元素入栈
+	stack.Push(1)
+	stack.Push(2)
+	stack.Push(3)
+	stack.Push(4)
+	stack.Push(5)
+	t.Log("栈 stack = ", stack.toString())
+
+	// 访问栈顶元素
+	peek := stack.Peek()
+	t.Log("栈顶元素 peek = ", peek)
+
+	// 元素出栈
+	pop := stack.Pop()
+	t.Log("出栈元素 pop  = ", pop, ", 出栈后 stack =", stack.toString())
+
+	// 获取栈的长度
+	size := stack.Size()
+	t.Log("栈的长度 size = ", size)
+
+	// 判断是否为空
+	isEmpty := stack.IsEmpty()
+	t.Log("栈是否为空 = ", isEmpty)
+}
+
+func TestLinkedListStack(t *testing.T) {
+
+}
+
+// BenchmarkStack 65.02 ns/op in Mac M1 Pro
+func BenchmarkStack(b *testing.B) {
+	stack := NewLinkedListStack()
+	// use b.N for looping
+	for i := 0; i < b.N; i++ {
+		stack.Push(777)
+	}
+	for i := 0; i < b.N; i++ {
+		stack.Pop()
+	}
+}
+
+// BenchmarkArrayStack 8 ns/op in Mac M1 Pro
+func BenchmarkArrayStack(b *testing.B) {
+	stack := NewArrayStack()
+	// use b.N for looping
+	for i := 0; i < b.N; i++ {
+		stack.Push(777)
+	}
+	for i := 0; i < b.N; i++ {
+		stack.Pop()
+	}
+}