feat: add BSTree which is binary search tree

datastructure/tree/bstree.go

@@ -0,0 +1,51 @@
+package datastructure
+
+import (
+	"math"
+
+	"github.com/duke-git/lancet/datastructure"
+	"github.com/duke-git/lancet/lancetconstraints"
+)
+
+// BSTree is a binary search tree data structure in which each node has at most two children,
+// which are referred to as the left child and the right child.
+// In BSTree: leftNode < rootNode < rightNode
+// type T should implments Compare function of lancetconstraints.Comparator interface
+type BSTree[T any] struct {
+	root *datastructure.TreeNode[T]
+}
+
+// NewBSTree create a BSTree pointer
+func NewBSTree[T any](rootData T) *BSTree[T] {
+	root := datastructure.NewTreeNode(rootData)
+	return &BSTree[T]{root}
+}
+
+// Insert data into BSTree
+func (t *BSTree[T]) Insert(data T, comparator lancetconstraints.Comparator) {
+	root := t.root
+	newNode := datastructure.NewTreeNode(data)
+	if root == nil {
+		t.root = newNode
+	} else {
+		insertTreeNode(root, newNode, comparator)
+	}
+}
+
+// NodeLevel get node level in BSTree
+func (t *BSTree[T]) NodeLevel(node *datastructure.TreeNode[T]) int {
+	if node == nil {
+		return 0
+	}
+	left := float64(t.NodeLevel(node.Left))
+	right := float64(t.NodeLevel(node.Right))
+
+	return int(math.Max(left, right)) + 1
+}
+
+// Print the bstree structure
+func (t *BSTree[T]) Print() {
+	maxLevel := t.NodeLevel(t.root)
+	nodes := []*datastructure.TreeNode[T]{t.root}
+	printTreeNodes(nodes, 1, maxLevel)
+}