code kata 230811

binary_tree_230809/main_test.go

@@ -92,6 +92,21 @@ func postOrder2(n *node) {
 	}
 }
 
+func levelOrder(n *node) {
+	q := MakeQueue()
+	q.EnQueue(n)
+	for !q.IsEmpty() {
+		p := q.DeQueue().(*node)
+		visit(p)
+		if p.left != nil {
+			q.EnQueue(p.left)
+		}
+		if p.right != nil {
+			q.EnQueue(p.right)
+		}
+	}
+}
+
 func TestPreOrder(t *testing.T) {
 	preOrder(makeBinary())
 }
@@ -116,6 +131,10 @@ func TestPostOrder2(t *testing.T) {
 	postOrder2(makeBinary())
 }
 
+func TestLevelOrder(t *testing.T) {
+	levelOrder(makeBinary())
+}
+
 func visit(n *node) {
 	if n == nil {
 		return

binary_tree_230809/queue.go

@@ -0,0 +1,28 @@
+package main
+
+type Queue []interface{}
+
+func MakeQueue() *Queue {
+	return &Queue{}
+}
+
+func (q Queue) Len() int {
+	return len(q)
+}
+
+func (q Queue) IsEmpty() bool {
+	return len(q) == 0
+}
+
+func (q *Queue) EnQueue(item interface{}) {
+	*q = append(append(*q, item))
+}
+
+func (q *Queue) DeQueue() interface{} {
+	if (*q).Len() == 0 {
+		return nil
+	}
+	item := (*q)[0]
+	*q = (*q)[1:len(*q)]
+	return item
+}

code_kata_230810/binary_tree_test.go

@@ -0,0 +1,168 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+func preOrder(n *node) {
+	if n == nil {
+		return
+	}
+	visit(n)
+	preOrder(n.left)
+	preOrder(n.right)
+}
+
+func preOrder2(n *node) {
+	stack := MakeStack()
+	p := n
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			visit(p)
+			stack.Push(p)
+			p = p.left
+		} else {
+			p = stack.Pop().(*node)
+			p = p.right
+		}
+	}
+}
+
+func inOrder(n *node) {
+	if n == nil {
+		return
+	}
+	inOrder(n.left)
+	visit(n)
+	inOrder(n.right)
+}
+
+func inOrder2(n *node) {
+	stack := MakeStack()
+	p := n
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			stack.Push(p)
+			p = p.left
+		} else {
+			p = stack.Pop().(*node)
+			visit(p)
+			p = p.right
+		}
+	}
+}
+
+func postOrder(n *node) {
+	if n == nil {
+		return
+	}
+	postOrder(n.left)
+	postOrder(n.right)
+	visit(n)
+}
+
+func postOrder2(n *node) {
+	stack := MakeStack()
+	p := n
+	var r *node = nil
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			stack.Push(p)
+			p = p.left
+		} else {
+			p = stack.Top().(*node)
+			if p.right != nil && p.right != r {
+				p = p.right
+				stack.Push(p)
+				p = p.left
+			} else {
+				p = stack.Pop().(*node)
+				visit(p)
+				r = p
+				p = nil
+			}
+		}
+	}
+}
+
+func levelOrder(n *node) {
+	queue := MakeQueue()
+	p := n
+	queue.EnQueue(p)
+	for !queue.IsEmpty() {
+		p = queue.DeQueue().(*node)
+		visit(p)
+		if p.left != nil {
+			queue.EnQueue(p.left)
+		}
+		if p.right != nil {
+			queue.EnQueue(p.right)
+		}
+	}
+}
+
+func TestPreOrder(t *testing.T) {
+	preOrder(makeBinaryTree())
+}
+
+func TestPreOrder2(t *testing.T) {
+	preOrder2(makeBinaryTree())
+}
+
+func TestInOrder(t *testing.T) {
+	inOrder(makeBinaryTree())
+}
+
+func TestInOrder2(t *testing.T) {
+	inOrder2(makeBinaryTree())
+}
+
+func TestPostOrder(t *testing.T) {
+	postOrder(makeBinaryTree())
+}
+
+func TestPostOrder2(t *testing.T) {
+	postOrder2(makeBinaryTree())
+}
+
+func TestLevelOrder(t *testing.T) {
+	levelOrder(makeBinaryTree())
+}
+
+type node struct {
+	left  *node
+	right *node
+	value string
+}
+
+func visit(n *node) {
+	if n == nil {
+		panic("invalid node")
+	}
+	fmt.Printf("Visiting node %s\n", n.value)
+}
+
+func makeBinaryTree() *node {
+	return &node{
+		left: &node{
+			left: &node{
+				value: "D",
+			},
+			right: &node{
+				value: "E",
+			},
+			value: "B",
+		},
+		right: &node{
+			left: &node{
+				value: "F",
+			},
+			right: &node{
+				value: "G",
+			},
+			value: "C",
+		},
+		value: "A",
+	}
+}

code_kata_230810/int_to_string_test.go

@@ -0,0 +1,37 @@
+package main
+
+import "testing"
+
+func IntToString(n int) string {
+	ret := make([]byte, 0)
+	for n > 0 {
+		ret = append([]byte{byte('0' + n%10)}, ret...)
+		n /= 10
+	}
+	//for l, r := 0, len(ret)-1; l < r; l, r = l+1, r-1 {
+	//	ret[l], ret[r] = ret[r], ret[l]
+	//}
+	return string(ret)
+}
+
+func TestIntToString(t *testing.T) {
+	tt := []struct {
+		name  string
+		input int
+		want  string
+	}{
+		{"1", 1, "1"},
+		{"11", 11, "11"},
+		{"112", 112, "112"},
+		{"11123456", 11123456, "11123456"},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			got := IntToString(tc.input)
+			if got != tc.want {
+				t.Errorf("IntToString(%d) = %s, want %s\n", tc.input, got, tc.want)
+			}
+		})
+	}
+}

code_kata_230810/prime_factors_test.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func PrimeFactorsOf(n int) []int {
+	ret := make([]int, 0)
+	d := 2
+	for d < n {
+		for n%d == 0 {
+			ret = append(ret, d)
+			n /= d
+		}
+		d++
+	}
+	if n > 1 {
+		ret = append(ret, n)
+	}
+	return ret
+}
+
+func TestPrimeFactorsOf(t *testing.T) {
+	tt := []struct {
+		name  string
+		input int
+		want  []int
+	}{
+		{"1", 1, []int{}},
+		{"2", 2, []int{2}},
+		{"4", 4, []int{2, 2}},
+		{"8", 8, []int{2, 2, 2}},
+		{"9", 9, []int{3, 3}},
+		{"a very large number", 2 * 3 * 17 * 37 * 71 * 73, []int{2, 3, 17, 37, 71, 73}},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			got := PrimeFactorsOf(tc.input)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("PrimeFactorsOf(%d) = %v, want %v\n", tc.input, got, tc.want)
+			}
+		})
+	}
+}

code_kata_230810/queue.go

@@ -0,0 +1,28 @@
+package main
+
+type Queue []interface{}
+
+func MakeQueue() *Queue {
+	return &Queue{}
+}
+
+func (q Queue) IsEmpty() bool {
+	return len(q) == 0
+}
+
+func (q Queue) Len() int {
+	return len(q)
+}
+
+func (q *Queue) EnQueue(item interface{}) {
+	*q = append(*q, item)
+}
+
+func (q *Queue) DeQueue() interface{} {
+	if q.IsEmpty() {
+		return nil
+	}
+	ret := (*q)[0]
+	*q = (*q)[1:]
+	return ret
+}

code_kata_230810/reverse_string_test.go

@@ -0,0 +1,32 @@
+package main
+
+import "testing"
+
+func ReverseString(s string) string {
+	r := []rune(s)
+	for l, e := 0, len(r)-1; l < e; l, e = l+1, e-1 {
+		r[l], r[e] = r[e], r[l]
+	}
+	return string(r)
+}
+
+func TestReverseString(t *testing.T) {
+	tt := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{"test", "test", "tset"},
+		{"testing", "testing", "gnitset"},
+		{"i am testing", "i am testing", "gnitset ma i"},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			got := ReverseString(tc.input)
+			if got != tc.want {
+				t.Errorf("ReverseString(%s) = %s, want %s\n", tc.input, got, tc.want)
+			}
+		})
+	}
+}

code_kata_230810/stack.go

@@ -0,0 +1,35 @@
+package main
+
+type Stack []interface{}
+
+func MakeStack() *Stack {
+	return &Stack{}
+}
+
+func (s Stack) IsEmpty() bool {
+	return len(s) == 0
+}
+
+func (s Stack) Len() int {
+	return len(s)
+}
+
+func (s Stack) Top() interface{} {
+	if s.IsEmpty() {
+		return nil
+	}
+	return s[len(s)-1]
+}
+
+func (s *Stack) Push(item interface{}) {
+	*s = append(*s, item)
+}
+
+func (s *Stack) Pop() interface{} {
+	if s.IsEmpty() {
+		return nil
+	}
+	ret := (*s)[len(*s)-1]
+	*s = (*s)[:len(*s)-1]
+	return ret
+}