add binary tree

Author: himanshub16

data-structures/binary-tree/binary-tree.go

@@ -0,0 +1,110 @@
+// basic binary tree and related operations
+
+package binarytree
+
+// package main
+
+import "fmt"
+
+type node struct {
+	val   int
+	left  *node
+	right *node
+}
+
+type btree struct {
+	root *node
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func newNode(val int) *node {
+	n := &node{val, nil, nil}
+	return n
+}
+
+func inorder(n *node) {
+	if n == nil {
+		return
+	}
+	inorder(n.left)
+	fmt.Print(n.val, " ")
+	inorder(n.right)
+}
+
+func preorder(n *node) {
+	if n == nil {
+		return
+	}
+	fmt.Print(n.val, " ")
+	inorder(n.left)
+	inorder(n.right)
+}
+
+func postorder(n *node) {
+	if n == nil {
+		return
+	}
+	inorder(n.left)
+	inorder(n.right)
+	fmt.Print(n.val, " ")
+}
+
+func levelorder(root *node) {
+	var q []*node // queue
+	var n *node   // temporary node
+
+	q = append(q, root)
+
+	for len(q) != 0 {
+		n, q = q[0], q[1:]
+		fmt.Print(n.val, " ")
+		if n.left != nil {
+			q = append(q, n.left)
+		}
+		if n.right != nil {
+			q = append(q, n.right)
+		}
+	}
+}
+
+// helper function for t.depth
+func _calculate_depth(n *node, depth int) int {
+	if n == nil {
+		return depth
+	}
+	return max(_calculate_depth(n.left, depth+1), _calculate_depth(n.right, depth+1))
+}
+
+func (t *btree) depth() int {
+	return _calculate_depth(t.root, 0)
+}
+
+/*
+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)
+
+	inorder(t.root)
+	fmt.Print("\n")
+	preorder(t.root)
+	fmt.Print("\n")
+	postorder(t.root)
+	fmt.Print("\n")
+	levelorder(t.root)
+	fmt.Print("\n")
+	fmt.Print(t.depth(), "\n")
+}
+*/