Merge pull request kelvins#213 from leandronsp/add-singly-linked-list-go

Add singly linked list in Go

Author: kelvins

README.md

@@ -2003,8 +2003,8 @@ Com o objetivo de alcançar uma abrangência maior e encorajar mais pessoas a co
                 </a>
             </td>
             <td> <!-- Go -->
-                <a href="./CONTRIBUTING.md">
-                    <img align="center" height="25" src="./logos/github.svg" />
+                <a href="./src/go/singly_linked_list.go">
+                    <img align="center" height="25" src="./logos/golang.svg" />
                 </a>
             </td>
             <td> <!-- Ruby -->

src/go/singly_linked_list.go

@@ -0,0 +1,165 @@
+package main
+
+import "fmt"
+
+type Node struct {
+	Value int
+	Next  *Node
+}
+
+type SinglyLinkedList struct {
+	Head *Node
+}
+
+func (list *SinglyLinkedList) AddLeft(value int) {
+	node := Node{Value: value}
+
+	if list.Head == nil {
+		list.Head = &node
+		return
+	}
+
+	node.Next = list.Head
+	list.Head = &node
+}
+
+func (list *SinglyLinkedList) AddRight(value int) {
+	node := Node{Value: value}
+
+	if list.Head == nil {
+		list.Head = &node
+		return
+	}
+
+	pointer := list.Head
+
+	for pointer.Next != nil {
+		pointer = pointer.Next
+	}
+
+	pointer.Next = &node
+}
+
+func (list *SinglyLinkedList) RemoveLeft() {
+	if list.Head == nil {
+		return
+	}
+
+	list.Head = list.Head.Next
+}
+
+func (list *SinglyLinkedList) RemoveRight() {
+	if list.Head == nil {
+		return
+	}
+
+	if list.Head.Next == nil {
+		list.Head = nil
+		return
+	}
+
+	pointer := list.Head
+
+	for pointer.Next.Next != nil {
+		pointer = pointer.Next
+	}
+
+	pointer.Next = nil
+}
+
+func (list *SinglyLinkedList) FindAt(idx int) *Node {
+	pointer := list.Head
+
+	for i := 0; i < idx; i++ {
+		pointer = pointer.Next
+		if pointer == nil {
+			return nil
+		}
+	}
+
+	return pointer
+}
+
+func (list *SinglyLinkedList) AddAt(idx, value int) {
+	if idx == 0 {
+		list.AddLeft(value)
+		return
+	}
+
+	prevNode := list.FindAt(idx - 1)
+
+	if prevNode == nil {
+		return
+	}
+
+	node := Node{Value: value}
+
+	node.Next = prevNode.Next
+	prevNode.Next = &node
+}
+
+func (list *SinglyLinkedList) RemoveAt(idx int) {
+	if idx == 0 {
+		list.RemoveLeft()
+		return
+	}
+
+	prevNode := list.FindAt(idx - 1)
+
+	if prevNode == nil {
+		return
+	}
+
+	prevNode.Next = prevNode.Next.Next
+}
+
+func (list *SinglyLinkedList) ToSlice() []int {
+	var slice []int
+
+	for pointer := list.Head; pointer != nil; pointer = pointer.Next {
+		slice = append(slice, pointer.Value)
+	}
+
+	return slice
+}
+
+func main() {
+	list := SinglyLinkedList{}
+
+	fmt.Println("AddLeft(1, 2)")
+	list.AddLeft(1)
+	list.AddLeft(2)
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("AddRight(3, 4)")
+	list.AddRight(3)
+	list.AddRight(4)
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("RemoveLeft()")
+	list.RemoveLeft()
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("RemoveRight()")
+	list.RemoveRight()
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("AddAt(1, 5)")
+	list.AddAt(1, 5)
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("RemoveAt(2)")
+	list.RemoveAt(2)
+
+	fmt.Println("list.toSlice(): ", list.ToSlice())
+
+	fmt.Println("FindAt(0)")
+	node := list.FindAt(0)
+	fmt.Println("node.Value: ", node.Value)
+
+}