Commiting so jcbwlkr can take a look

go/custom-set/cmd/main.go

@@ -8,42 +8,22 @@ import (
 
 func main() {
 	fmt.Println("Creating Set 1")
-	s1 := stringset.NewFromSlice([]string{"a", "b"})
+	s1 := stringset.NewFromSlice([]string{"a"})
-	addAndOutput(s1, "A")
+	addAndOutput(s1, "b")
+	addAndOutput(s1, "d")
+	s1.PrettyPrint()
+	return
 	addAndOutput(s1, "c")
-	addAndOutput(s1, "B")
+	addAndOutput(s1, "0")
-	addAndOutput(s1, "B1")
+	addAndOutput(s1, "aa")
-	addAndOutput(s1, "A1")
+	addAndOutput(s1, "aaa")
-	addAndOutput(s1, "B2")
-	addAndOutput(s1, "A2")
-	addAndOutput(s1, "B3")
-	addAndOutput(s1, "A3")
-	delAndOutput(s1, "a")
-
-	fmt.Println("Creating Set 2")
-	s2 := stringset.NewFromSlice([]string{"A", "c"})
-	addAndOutput(s2, "a")
-	addAndOutput(s2, "b")
-	addAndOutput(s2, "B1")
-	addAndOutput(s2, "A3")
-	addAndOutput(s2, "A2")
-	addAndOutput(s2, "B2")
-	addAndOutput(s2, "A1")
-	addAndOutput(s2, "B3")
-	addAndOutput(s2, "B")
-	s2.PrettyPrint()
-	delAndOutput(s2, "a")
-	s2.PrettyPrint()
 }
 
-func addAndOutput(s *stringset.Set, val string) {
+func addAndOutput(s stringset.Set, val string) {
-	fmt.Println("Adding " + val)
+	fmt.Println("Adding new value: " + val)
 	s.Add(val)
-	fmt.Println(s.String())
 }
 
-func delAndOutput(s *stringset.Set, val string) {
+func delAndOutput(s stringset.Set, val string) {
-	fmt.Println("Deleting " + val)
 	s.Delete(val)
-	fmt.Println(s.String())
 }

go/custom-set/custom_set_test.go

@@ -27,6 +27,7 @@ package stringset
 // Format the empty set as {}.
 
 import (
+	"fmt"
 	"math/rand"
 	"reflect"
 	"strconv"
@@ -166,13 +167,17 @@ func TestEqual(t *testing.T) {
 // helper for testing Add, Delete
 func testEleOp(name string, op func(Set, string), cases []eleOpCase, t *testing.T) {
 	for _, tc := range cases {
+		fmt.Print("Running Test Case: ")
+		fmt.Println(tc)
 		s := NewFromSlice(tc.set)
 		op(s, tc.ele)
 		want := NewFromSlice(tc.want)
 		if !Equal(s, want) {
+			fmt.Println(s.String())
 			t.Fatalf("%v %s %q = %v, want %v",
 				NewFromSlice(tc.set), name, tc.ele, s, want)
 		}
+		fmt.Println("=== Done ===")
 	}
 }
 

go/custom-set/stringset.go

@@ -3,6 +3,7 @@ package stringset
 import (
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 )
 
@@ -11,30 +12,30 @@ const testVersion = 3
 // Set is a slice of strings that you can do set operations on.
 // I decided that I wanted to implement a binary tree for the storage
 type Set struct {
-	top SetValue
+	top *Node
 }
 
-type SetValue struct {
+type Node struct {
 	value string
-	left  *SetValue
+	left  *Node
-	right *SetValue
+	right *Node
 }
 
 // New returns an empty Set
 func New() Set {
 	s := new(Set)
-	s.top = SetValue{}
+	s.top = &Node{}
 	return *s
 }
 
 // NewFromSlice takes a slice of strings and returns a Set
 func NewFromSlice(s []string) Set {
 	ret := New()
+	r := &ret
 	for i := range s {
-		ret.Add(s[i])
+		r.Add(s[i])
 	}
-	ret.balance()
+	return *r
-	return ret
 }
 
 // Add adds a value to the set
@@ -43,71 +44,32 @@ func (s Set) Add(v string) {
 		s.top.value = v
 		return
 	}
-	s.top.Add(v)
+	if !s.Has(v) {
-}
+		bef := "Current Top Node: " + s.top.value + ";L:" + s.top.getLeftValue() + ";R:" + s.top.getRightValue()
+		newNode := s.top.Add(&Node{value: v})
+		fmt.Println(bef)
+		fmt.Println("Current New Node: " + newNode.value + ";L:" + newNode.getLeftValue() + ";R:" + newNode.getRightValue())
+		fmt.Printf("newNode.left: %v (%v)\n", &newNode.left, newNode.left)
+		s.top.value = newNode.value
+		s.top.left = newNode.left
+		s.top.right = newNode.right
+		fmt.Println("Current Top Node: " + s.top.value + ";L:" + s.top.getLeftValue() + ";R:" + s.top.getRightValue())
+		fmt.Printf("s.top.left: %v (%v)\n", &s.top.left, s.top.left)
+		fmt.Println("Add Done")
 
-func (s *Set) PrettyPrint() {
+		//s.top = s.top.Add(newNode)
-	s.pp(&s.top, 0)
+		//fmt.Println("Current Top Node: " + s.top.value + ";L:" + s.top.getLeftValue() + ";R:" + s.top.getRightValue())
-}
-
-func (s *Set) pp(n *SetValue, indent int) {
-	if n != nil {
-		if n.left != nil {
-			s.pp(n.left, indent+4)
-		}
-		if n.right != nil {
-			s.pp(n.right, indent+4)
-		}
-		for ; indent > 0; indent-- {
-			fmt.Print(" ")
-		}
-		fmt.Println(n.value)
 	}
 }
 
-// balance balances the binary tree
-func (s *Set) balance() {
-
-}
-
-func (s *Set) find(v string) *SetValue {
-	if s.top.value != "" {
-		sv, _ := s.top.find(v)
-		return sv
-	}
-	return nil
-}
-
-// findWithParent finds a node with a child value v
-// a return of nil, nil means it's the top node
-func (s *Set) findParent(v string) (*SetValue, error) {
-	if s.top.value == v {
-		// no parent, it's the top.
-		return nil, nil
-	} else {
-		return s.top.findParent(v)
-	}
-	return nil, errors.New("Empty Set")
-}
-
-func (s *Set) findHome(v *SetValue) {
-	if s.top.value == "" {
-		s.top.value = v.value
-		s.top.left = v.left
-		s.top.right = v.right
-		return
-	}
-	s.top.findHome(v)
-}
-
 // Delete removes the given value from the set
 func (s Set) Delete(v string) {
 	if sv, err := s.findParent(v); err == nil {
 		var cmp int
-		var delNode, repNode, orphan *SetValue
+		var delNode, repNode, orphan *Node
 		if sv == nil {
 			// Deleting 'top'
-			delNode = &s.top
+			delNode = s.top
 			if delNode.left != nil {
 				repNode = delNode.left
 				orphan = delNode.right
@@ -118,15 +80,13 @@ func (s Set) Delete(v string) {
 				// No node to replace it with, we're done
 				return
 			}
-			s.top = *repNode
+			s.top = repNode
 		} else {
 			cmp = strings.Compare(v, sv.value)
 			if cmp < 0 && sv.left != nil {
-				fmt.Println("    Left: " + sv.left.value)
 				// It's the left node
 				delNode = sv.left
 			} else if cmp > 0 && sv.right != nil {
-				fmt.Println("    Right: " + sv.right.value)
 				// It's the right node
 				delNode = sv.right
 			}
@@ -157,6 +117,62 @@ func (s Set) Delete(v string) {
 	}
 }
 
+func (s Set) PrettyPrint() {
+	fmt.Println("=========")
+	s.pp(s.top, 0)
+	fmt.Println("=========")
+}
+
+func (s Set) pp(n *Node, indent int) {
+	if n.left == n || n.right == n {
+		// Circular reference...
+		fmt.Println("Circular reference... You done messed up.")
+		return
+	}
+	if n != nil {
+		if n.left != nil {
+			s.pp(n.left, indent+4)
+		}
+		if n.right != nil {
+			s.pp(n.right, indent+4)
+		}
+		for ; indent > 0; indent-- {
+			fmt.Print(" ")
+		}
+		fmt.Println(n.value)
+	}
+}
+
+func (s *Set) find(v string) *Node {
+	if s.top.value != "" {
+		sv, _ := s.top.find(v)
+		return sv
+	}
+	return nil
+}
+
+// findWithParent finds a node with a child value v
+// a return of nil, nil means it's the top node
+func (s *Set) findParent(v string) (*Node, error) {
+	if s.top.value == v {
+		// no parent, it's the top.
+		return nil, nil
+	} else {
+		return s.top.findParent(v)
+	}
+	return nil, errors.New("Empty Set")
+}
+
+func (s *Set) findHome(v *Node) {
+	if s.top.value == "" {
+		s.top.value = v.value
+		s.top.left = v.left
+		s.top.right = v.right
+		return
+	}
+	s.top.findHome(v)
+}
+
 // Has returns if the set contains the given value.
 func (s *Set) Has(v string) bool {
 	return s.find(v) != nil
@@ -195,7 +211,7 @@ func (s Set) String() string {
 
 // find looks for a node with value val, it either returns the node
 // or an error stating it couldn't find it.
-func (sv *SetValue) find(val string) (*SetValue, error) {
+func (sv *Node) find(val string) (*Node, error) {
 	if sv.value == val {
 		return sv, nil
 	}
@@ -211,7 +227,7 @@ func (sv *SetValue) find(val string) (*SetValue, error) {
 
 // findParent looks for the parent of the node with value val
 // If nil, nil is returned, it _is_ this node.
-func (sv *SetValue) findParent(val string) (*SetValue, error) {
+func (sv *Node) findParent(val string) (*Node, error) {
 	if sv.value == val {
 		// This should only trigger if this is the top node of the tree
 		return nil, nil
@@ -232,7 +248,7 @@ func (sv *SetValue) findParent(val string) (*SetValue, error) {
 	return nil, errors.New("Value not found")
 }
 
-func (sv *SetValue) findHome(v *SetValue) {
+func (sv *Node) findHome(v *Node) {
 	cmp := strings.Compare(v.value, sv.value)
 	if cmp < 0 {
 		if sv.left == nil {
@@ -257,25 +273,86 @@ func (sv *SetValue) findHome(v *SetValue) {
 	}
 }
 
-func (sv *SetValue) Add(v string) {
+func (sv *Node) Add(n *Node) *Node {
-	cmp := strings.Compare(v, sv.value)
+	fmt.Println("1 Adding at Node " + sv.value)
+	cmp := strings.Compare(n.value, sv.value)
 	if cmp < 0 {
+		fmt.Println("2 checking to left")
 		if sv.left == nil {
-			sv.left = &SetValue{value: v}
+			fmt.Println("3 left is nil, add it")
+			sv.left = n
 		} else {
-			sv.left.Add(v)
+			fmt.Println("--> 4 recurse left")
+			sv.left = sv.left.Add(n)
+			fmt.Println("<-- 5 added to left")
 		}
-	} else if cmp > 0 {
+	} else {
+		fmt.Println("6 checking to right")
 		if sv.right == nil {
-			sv.right = &SetValue{value: v}
+			fmt.Println("7 right is nil, add it")
+			sv.right = n
 		} else {
-			sv.right.Add(v)
+			fmt.Println("--> 8 recurse right")
+			sv.right = sv.right.Add(n)
+			fmt.Println("<-- 9 added to right")
 		}
 	}
+
+	fmt.Println("10 let's balance now (sv: " + sv.value + ")")
+	balance := GetBalance(sv)
+	// left left unbalance
+	fmt.Println("11 balance: " + strconv.Itoa(balance))
+	newVal := sv
+	if balance > 1 && strings.Compare(n.value, sv.getLeftValue()) < 0 { // < sv.left.value {
+		fmt.Println("12 Left Left")
+		newVal = RightRotate(sv)
+		fmt.Println("13")
+	}
+	// right right unbalance
+	if balance < -1 && strings.Compare(n.value, sv.getRightValue()) > 0 { //n.value > sv.right.value {
+		fmt.Println("14 Right Right")
+		newVal = LeftRotate(sv)
+		fmt.Println("15")
+	}
+	// left right unbalance
+	if balance > 1 && strings.Compare(n.value, sv.getLeftValue()) > 0 { //n.value > sv.left.value {
+		fmt.Println("16 Left Right")
+		sv.left = LeftRotate(sv.left)
+		fmt.Println("17")
+		newVal = RightRotate(sv)
+		fmt.Println("18")
+	}
+	// right left unbalance
+	if balance < -1 && strings.Compare(n.value, sv.getRightValue()) < 0 { //n.value < sv.right.value {
+		fmt.Println("19 Right Left")
+		sv.right = RightRotate(sv.right)
+		fmt.Println("20")
+		newVal = LeftRotate(sv)
+		fmt.Println("21")
+	}
+	fmt.Println("22 end add")
+	return newVal
+}
+
+func (sv *Node) getLeftValue() string {
+	if sv.left == nil {
+		return ""
+	}
+	return sv.left.value
+}
+
+func (sv *Node) getRightValue() string {
+	if sv.right == nil {
+		return ""
+	}
+	return sv.right.value
 }
 
 // Len returns how many elements are in the branches
-func (sv *SetValue) Len() int {
+func (sv *Node) Len() int {
+	if sv == nil {
+		return 0
+	}
 	ret := 1
 	if sv.left != nil {
 		ret += sv.left.Len()
@@ -287,26 +364,34 @@ func (sv *SetValue) Len() int {
 }
 
 // Has checks if this branch contains the value v
-func (sv *SetValue) Has(v string) bool {
+func (sv *Node) Has(v string) bool {
 	ret, _ := sv.find(v)
 	return ret != nil
 }
 
 // String gets a string value of this branch
-func (sv *SetValue) String() string {
+func (sv *Node) String() string {
 	var ret string
 	if sv.left != nil {
-		ret += sv.left.String() + ", "
+		if sv.left == sv {
+			ret += "**, "
+		} else {
+			ret += sv.left.String() + ", "
+		}
 	}
 	ret += "\"" + sv.value + "\""
 	if sv.right != nil {
-		ret += ", " + sv.right.String()
+		if sv.right == sv {
+			ret += "**, "
+		} else {
+			ret += ", " + sv.right.String()
+		}
 	}
 	return ret
 }
 
 // Slice returns a string slice of all values in the branch
-func (sv *SetValue) Slice() []string {
+func (sv *Node) Slice() []string {
 	var ret []string
 	if sv.left != nil {
 		ret = sv.left.Slice()
@@ -325,9 +410,6 @@ func Equal(s1, s2 Set) bool {
 
 // Subset returns whether s1 is a subset of s2.
 func Subset(s1, s2 Set) bool {
-	if s1.Len() == 0 || s2.Len() == 0 {
-		return false
-	}
 	s1Sl := s1.Slice()
 	for i := range s1Sl {
 		if !s2.Has(s1Sl[i]) {
@@ -345,7 +427,7 @@ func Disjoint(s1, s2 Set) bool {
 			return false
 		}
 	}
-	return false
+	return true
 }
 
 // Intersection finds elements that exist in both sets and makes a new
@@ -386,3 +468,41 @@ func Difference(s1, s2 Set) Set {
 func SymmetricDifference(s1, s2 Set) Set {
 	return Union(Difference(s1, s2), Difference(s2, s1))
 }
+
+/* Helper Functions for Balancing the Tree */
+func RightRotate(y *Node) *Node {
+	x := y.left
+	t2 := x.right
+	// Perform rotation
+	x.right = y
+	y.left = t2
+	fmt.Println("RightRotate: return=" + x.value + "; L:" + x.left.value + "; R:" + x.right.value)
+	fmt.Println("RightRotate: leftNode=" + x.getLeftValue() + "; L:" + x.left.getLeftValue() + "; R:" + x.left.getRightValue())
+	fmt.Println("RightRotate: rightNode=" + x.getRightValue() + "; L:" + x.right.getLeftValue() + "; R:" + x.right.getRightValue())
+	// Return new root
+	return x
+}
+
+func LeftRotate(x *Node) *Node {
+	y := x.right
+	t2 := y.left
+	// Perform rotation
+	y.left = x
+	x.right = t2
+	// Return new root
+	fmt.Println("LeftRotate: return=" + y.value + "; L:" + y.left.value + "; R:" + y.right.value)
+	fmt.Println("LeftRotate: leftNode=" + y.getLeftValue() + "; L:" + y.left.getLeftValue() + "; R:" + y.left.getRightValue())
+	fmt.Println("LeftRotate: rightNode=" + y.getRightValue() + "; L:" + y.right.getLeftValue() + "; R:" + y.right.getRightValue())
+	return y
+}
+
+func GetBalance(n *Node) int {
+	if n == nil {
+		return 0
+	}
+	return n.left.Len() - n.right.Len()
+}
+
+func CompareNodes(n1, n2 *Node) int {
+	return strings.Compare(n1.value, n2.value)
+}