code kata 20230805

binary_tree_230804/main_test.go

@@ -0,0 +1,169 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+type node struct {
+	left  *node
+	right *node
+	value string
+}
+
+func preOrder(n *node) {
+	if n != nil {
+		visit(n)
+		preOrder(n.left)
+		preOrder(n.right)
+	}
+}
+
+func preOrder2(n *node) {
+	stack := NewStack()
+	p := n
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			stack.Push(p)
+			visit(p)
+			p = p.left
+		} else {
+			x, err := stack.Pop()
+			if err != nil {
+				fmt.Print(err.Error())
+				p = nil
+				break
+			}
+			p = x.(*node)
+			p = p.right
+		}
+	}
+}
+
+func inOrder(n *node) {
+	if n != nil {
+		inOrder(n.left)
+		visit(n)
+		inOrder(n.right)
+	}
+}
+
+func inOrder2(n *node) {
+	stack := NewStack()
+	p := n
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			stack.Push(p)
+			p = p.left
+		} else {
+			x, err := stack.Pop()
+			if err != nil {
+				fmt.Print(err.Error())
+				p = nil
+				break
+			}
+			p = x.(*node)
+			visit(p)
+			p = p.right
+		}
+	}
+}
+
+func postOrder(n *node) {
+	if n != nil {
+		postOrder(n.left)
+		postOrder(n.right)
+		visit(n)
+	}
+}
+
+func postOrder2(n *node) {
+	stack := NewStack()
+	p := n
+	var r *node = nil
+	for p != nil || !stack.IsEmpty() {
+		if p != nil {
+			stack.Push(p)
+			p = p.left
+		} else {
+			x := stack.Top()
+			if x == nil {
+				break
+			}
+			p = x.(*node)
+			if p.right != nil && p.right != r {
+				p = p.right
+				stack.Push(p)
+				p = p.left
+			} else {
+				x, err := stack.Pop()
+				if err != nil {
+					fmt.Print(err.Error())
+					p = nil
+					break
+				}
+				p = x.(*node)
+				visit(p)
+				r = p
+				p = nil
+			}
+		}
+	}
+}
+
+func visit(n *node) {
+	fmt.Printf("Visiting Node: %s\n", n.value)
+}
+
+func makeBinaryTree() *node {
+	ln1 := &node{
+		value: "D",
+	}
+	ln2 := &node{
+		value: "E",
+	}
+	ln := &node{
+		value: "B",
+		left:  ln1,
+		right: ln2,
+	}
+	rn := &node{
+		value: "C",
+	}
+	n := &node{
+		value: "A",
+		left:  ln,
+		right: rn,
+	}
+	return n
+}
+
+func TestPreOrder(t *testing.T) {
+	n := makeBinaryTree()
+	preOrder(n)
+}
+
+func TestPreOrder2(t *testing.T) {
+	n := makeBinaryTree()
+	preOrder2(n)
+}
+
+func TestInOrder(t *testing.T) {
+	n := makeBinaryTree()
+	inOrder(n)
+}
+
+func TestInOrder2(t *testing.T) {
+	n := makeBinaryTree()
+	inOrder2(n)
+}
+
+func TestPostOrder(t *testing.T) {
+	n := makeBinaryTree()
+	postOrder(n)
+}
+
+func TestPostOrder2(t *testing.T) {
+	n := makeBinaryTree()
+	postOrder2(n)
+}

binary_tree_230804/stack.go

@@ -0,0 +1,39 @@
+package main
+
+import "errors"
+
+type Stack []interface {
+}
+
+func NewStack() Stack {
+	return Stack{}
+}
+
+func (s Stack) IsEmpty() bool {
+	return len(s) == 0
+}
+
+func (s *Stack) Push(item interface{}) error {
+	*s = append(*s, item)
+	return nil
+}
+
+func (s *Stack) Pop() (interface{}, error) {
+	if s.IsEmpty() {
+		return nil, errors.New("stack is empty")
+	}
+	ret := (*s)[len(*s)-1]
+	*s = (*s)[:len(*s)-1]
+	return ret, nil
+}
+
+func (s Stack) Top() interface{} {
+	if s.IsEmpty() {
+		return nil
+	}
+	return s[len(s)-1]
+}
+
+func (s Stack) Len() int {
+	return len(s)
+}

prime_factors_230805/main_test.go

@@ -0,0 +1,45 @@
+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}},
+		{"6", 6, []int{2, 3}},
+		{"8", 8, []int{2, 2, 2}},
+		{"9", 9, []int{3, 3}},
+		{"a very large number", 2 * 3 * 5 * 17 * 71 * 73, []int{2, 3, 5, 17, 71, 73}},
+	}
+
+	for _, tc := range tt {
+		got := PrimeFactorsOf(tc.input)
+		if !reflect.DeepEqual(got, tc.want) {
+			t.Errorf("PrimeFactorsOf(%d) = %v, want %v", tc.input, got, tc.want)
+		}
+	}
+}

reverse_string_230805/main_test.go

@@ -0,0 +1,33 @@
+package main
+
+import "testing"
+
+func ReverseString(s string) string {
+	tmp := []rune(s)
+	l := len(tmp)
+	for i := 0; i < l/2; i++ {
+		tmp[i], tmp[l-i-1] = tmp[l-i-1], tmp[i]
+	}
+	return string(tmp)
+}
+
+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", tc.input, got, tc.want)
+			}
+		})
+	}
+}