Add Go codes to docs, including

the chapter of stack and queue, the chapter of tree.

codes/go/pkg/tree_node.go

@@ -6,7 +6,6 @@ package pkg
 
 import (
 	"container/list"
-	"fmt"
 )
 
 type TreeNode struct {
@@ -71,58 +70,3 @@ func TreeToArray(root *TreeNode) []any {
 	}
 	return arr
 }
-
-// PrintTree Print a binary tree
-func PrintTree(root *TreeNode) {
-	printTreeHelper(root, nil, false)
-}
-
-// printTreeHelper Help to print a binary tree, hide more details
-// This tree printer is borrowed from TECHIE DELIGHT
-// https://www.techiedelight.com/c-program-print-binary-tree/
-func printTreeHelper(root *TreeNode, prev *trunk, isLeft bool) {
-	if root == nil {
-		return
-	}
-	prevStr := "    "
-	trunk := newTrunk(prev, prevStr)
-	printTreeHelper(root.Right, trunk, true)
-	if prev == nil {
-		trunk.str = "———"
-	} else if isLeft {
-		trunk.str = "/———"
-		prevStr = "   |"
-	} else {
-		trunk.str = "\\———"
-		prev.str = prevStr
-	}
-	showTrunk(trunk)
-	fmt.Println(root.Val)
-	if prev != nil {
-		prev.str = prevStr
-	}
-	trunk.str = "   |"
-	printTreeHelper(root.Left, trunk, false)
-}
-
-// trunk Help to Print tree structure
-type trunk struct {
-	prev *trunk
-	str  string
-}
-
-func newTrunk(prev *trunk, str string) *trunk {
-	return &trunk{
-		prev: prev,
-		str:  str,
-	}
-}
-
-func showTrunk(t *trunk) {
-	if t == nil {
-		return
-	}
-
-	showTrunk(t.prev)
-	fmt.Print(t.str)
-}