From e99571482691b80047606fdba1b68a4fc67ec95d Mon Sep 17 00:00:00 2001
From: Pavel <kositsyn.pa@phystech.edu>
Date: Sun, 20 Feb 2022 02:23:36 +0300
Subject: [PATCH] Initial for treeiter

---
 go.mod                            |  2 +-
 treeiter/README.md                | 16 +++++++
 treeiter/treeiter.go              |  4 ++
 treeiter/treeiter_example_test.go | 24 ++++++++++
 treeiter/treeiter_test.go         | 77 +++++++++++++++++++++++++++++++
 5 files changed, 122 insertions(+), 1 deletion(-)
 create mode 100644 treeiter/README.md
 create mode 100644 treeiter/treeiter.go
 create mode 100644 treeiter/treeiter_example_test.go
 create mode 100644 treeiter/treeiter_test.go

diff --git a/go.mod b/go.mod
index aa5c5f7..15928df 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module gitlab.com/slon/shad-go
 
-go 1.17
+go 1.18
 
 require (
 	github.com/ClickHouse/clickhouse-go v1.4.0
diff --git a/treeiter/README.md b/treeiter/README.md
new file mode 100644
index 0000000..0ef2213
--- /dev/null
+++ b/treeiter/README.md
@@ -0,0 +1,16 @@
+# treeiter
+
+В этой задаче нужно написать итератор по бинарному дереву.
+Это дерево удовлетворяет следующему интерфейсу и само является типом `T` в нем:
+
+```go
+type Node[T any] interface {
+    Left() *T
+    Right() *T
+}
+```
+
+Итератор должен принимать на вход дерево и 
+функцию с одним аргументом типа дерева, не возвращающую ничего.
+
+Пример использования итератора можно посмотреть в `treeiter_example_test.go`
diff --git a/treeiter/treeiter.go b/treeiter/treeiter.go
new file mode 100644
index 0000000..0cf96f2
--- /dev/null
+++ b/treeiter/treeiter.go
@@ -0,0 +1,4 @@
+//go:build !solution
+// +build !solution
+
+package treeiter
diff --git a/treeiter/treeiter_example_test.go b/treeiter/treeiter_example_test.go
new file mode 100644
index 0000000..95724fc
--- /dev/null
+++ b/treeiter/treeiter_example_test.go
@@ -0,0 +1,24 @@
+package treeiter
+
+import "fmt"
+
+func ExampleDoInOrder() {
+	tree := &ValuesNode[string]{
+		value: "root",
+		left: &ValuesNode[string]{
+			value: "left",
+		},
+		right: &ValuesNode[string]{
+			value: "right",
+		},
+	}
+
+	DoInOrder(tree, func(t *ValuesNode[string]) {
+		fmt.Println(t.value)
+	})
+
+	// Output:
+	// left
+	// root
+	// right
+}
diff --git a/treeiter/treeiter_test.go b/treeiter/treeiter_test.go
new file mode 100644
index 0000000..d1cba09
--- /dev/null
+++ b/treeiter/treeiter_test.go
@@ -0,0 +1,77 @@
+package treeiter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type Node[T any] interface {
+	Left() *T
+	Right() *T
+}
+
+type ValuesNode[T any] struct {
+	value       T
+	left, right *ValuesNode[T]
+}
+
+var _ Node[ValuesNode[any]] = (*ValuesNode[any])(nil)
+
+func (t ValuesNode[T]) Left() *ValuesNode[T] {
+	return t.left
+}
+
+func (t ValuesNode[T]) Right() *ValuesNode[T] {
+	return t.right
+}
+
+type Collector[T any] struct {
+	nodes []*ValuesNode[T]
+}
+
+func (c *Collector[T]) Collect(tree *ValuesNode[T]) {
+	c.nodes = append(c.nodes, tree)
+}
+
+func TestInOrderNil(t *testing.T) {
+	var collector Collector[any]
+	DoInOrder(nil, collector.Collect)
+}
+
+func TestInOrderIntTree(t *testing.T) {
+	root := &ValuesNode[int]{value: 1}
+	collector := Collector[int]{}
+
+	DoInOrder(root, collector.Collect)
+
+	assert.Equal(t, []*ValuesNode[int]{{value: 1}}, collector.nodes)
+}
+
+func TestInOrderStringTree(t *testing.T) {
+	rightLeftRight := &ValuesNode[string]{
+		value: "right left right",
+	}
+	rightLeft := &ValuesNode[string]{
+		value: "right left",
+		right: rightLeftRight,
+	}
+	right := &ValuesNode[string]{
+		value: "right",
+		left:  rightLeft,
+	}
+	left := &ValuesNode[string]{
+		value: "left",
+	}
+
+	root := &ValuesNode[string]{
+		value: "root",
+		left:  left,
+		right: right,
+	}
+	var collector Collector[string]
+
+	DoInOrder(root, collector.Collect)
+
+	assert.Equal(t, []*ValuesNode[string]{left, root, rightLeft, rightLeftRight, right}, collector.nodes)
+}