Update some functions in the btree directory (#334)

Co-authored-by: Yaolin_Li <1586505611@qq.com>
Co-authored-by: Andrii Siriak <siryaka@gmail.com>
Co-authored-by: Rak Laptudirm <raklaptudirm@gmail.com>

data_structures/binary_tree/binarysearchtree.go

@@ -8,31 +8,30 @@ package binarytree
 // )
 
 // func main() {
-// 	t := &BTree{nil}
-// 	InOrder(t.root)
-// 	t.root = Insert(t.root, 30)
-
-// 	t.root = Insert(t.root, 20)
-// 	t.root = Insert(t.root, 15)
-// 	t.root = Insert(t.root, 10)
-// 	t.root = Insert(t.root, 12)
-// 	t.root = Insert(t.root, 9)
-// 	t.root = Insert(t.root, 11)
-// 	t.root = Insert(t.root, 17)
-// 	fmt.Print(t.depth(), "\n")
-// 	InOrder(t.root)
-// 	fmt.Print("\n")
-// 	t.root = BstDelete(t.root, 10)
-// 	InOrder(t.root)
-// 	fmt.Print("\n")
-// 	t.root = BstDelete(t.root, 30)
-// 	InOrder(t.root)
-// 	fmt.Print("\n")
-// 	t.root = BstDelete(t.root, 15)
-// 	InOrder(t.root)
-// 	fmt.Print("\n")
-// 	t.root = BstDelete(t.root, 20)
-// 	InOrder(t.root)
-// 	fmt.Print("\n")
-// 	fmt.Print(t.depth(), "\n")
+//t := &BTree{nil}
+//InOrder(t.Root)
+//t.Root = Insert(t.Root, 30)
+//t.Root = Insert(t.Root, 20)
+//t.Root = Insert(t.Root, 15)
+//t.Root = Insert(t.Root, 10)
+//t.Root = Insert(t.Root, 12)
+//t.Root = Insert(t.Root, 9)
+//t.Root = Insert(t.Root, 11)
+//t.Root = Insert(t.Root, 17)
+//fmt.Print(t.Depth(), "\n")
+//InOrder(t.Root)
+//fmt.Print("\n")
+//t.Root = BstDelete(t.Root, 10)
+//InOrder(t.Root)
+//fmt.Print("\n")
+//t.Root = BstDelete(t.Root, 30)
+//InOrder(t.Root)
+//fmt.Print("\n")
+//t.Root = BstDelete(t.Root, 15)
+//InOrder(t.Root)
+//fmt.Print("\n")
+//t.Root = BstDelete(t.Root, 20)
+//InOrder(t.Root)
+//fmt.Print("\n")
+//fmt.Print(t.Depth(), "\n")
 // }

data_structures/binary_tree/binarytree.go

@@ -3,24 +3,36 @@ package binarytree
 
 /*
 func main() {
-	t := btree{nil}
-	t.root = newNode(0)
-	t.root.left = newNode(1)
-	t.root.right = newNode(2)
-	t.root.left.left = newNode(3)
-	t.root.left.right = newNode(4)
-	t.root.right.left = newNode(5)
-	t.root.right.right = newNode(6)
-	t.root.right.right.right = newNode(10)
+	t := BTree{nil}
+	t.Root = NewNode(0)
+	t.Root.left = NewNode(1)
+	t.Root.right = NewNode(2)
+	t.Root.left.left = NewNode(3)
+	t.Root.left.right = NewNode(4)
+	t.Root.right.left = NewNode(5)
+	t.Root.right.right = NewNode(6)
+	t.Root.right.right.right = NewNode(10)
 
-	inorder(t.root)
+	InOrder(t.Root)
 	fmt.Print("\n")
-	preorder(t.root)
+	PreOrder(t.Root)
 	fmt.Print("\n")
-	postorder(t.root)
+	PostOrder(t.Root)
 	fmt.Print("\n")
-	levelorder(t.root)
+	LevelOrder(t.Root)
 	fmt.Print("\n")
-	fmt.Print(t.depth(), "\n")
+	fmt.Print(t.Depth(), "\n")
+	var list = AccessNodesByLayer(t.Root)
+	fmt.Println("{")
+	for i, v := range list {
+		for _, v2 := range v {
+			fmt.Print(" [", v2, "]")
+		}
+		if i != len(list)-1 {
+			fmt.Print(",")
+		}
+		fmt.Println()
+	}
+	fmt.Println("}")
 }
 */

data_structures/binary_tree/btree.go

@@ -116,6 +116,35 @@ func LevelOrder(root *Node) {
 	}
 }
 
+// AccessNodesByLayer Function that access nodes layer by layer instead of printing the results as one line.
+func AccessNodesByLayer(root *Node) [][]int {
+	var res [][]int
+	if root == nil {
+		return res
+	}
+	var q []*Node
+	var n *Node
+	var idx = 0
+	q = append(q, root)
+
+	for len(q) != 0 {
+		res = append(res, []int{})
+		qLen := len(q)
+		for i := 0; i < qLen; i++ {
+			n, q = q[0], q[1:]
+			res[idx] = append(res[idx], n.val)
+			if n.left != nil {
+				q = append(q, n.left)
+			}
+			if n.right != nil {
+				q = append(q, n.right)
+			}
+		}
+		idx++
+	}
+	return res
+}
+
 // Max Function that returns max of two numbers - possibly already declared.
 func Max(a, b int) int {
 	if a > b {