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- unexporting node struct and color constants (keeping the lib clean)

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Emir Pasic 2015-03-05 05:27:36 +01:00
parent e04668c20d
commit 14efefae45
1 changed files with 74 additions and 74 deletions
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148
trees/redblacktree/redblacktree.go
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@ -27,25 +27,25 @@ import (
"github.com/emirpasic/gods/utils" "github.com/emirpasic/gods/utils"
) )
type Color bool type color bool
const ( const (
BLACK, RED Color = true, false black, red color = true, false
) )
type Tree struct { type Tree struct {
root *Node root *node
size int size int
comparator utils.Comparator comparator utils.Comparator
} }
type Node struct { type node struct {
key interface{} key interface{}
value interface{} value interface{}
color Color color color
left *Node left *node
right *Node right *node
parent *Node parent *node
} }
// Instantiates a red-black tree with the custom comparator. // Instantiates a red-black tree with the custom comparator.
@ -66,7 +66,7 @@ func NewWithStringComparator() *Tree {
// Inserts node into the tree. // Inserts node into the tree.
// Key should adhere to the comparator's type assertion, otherwise method panics. // Key should adhere to the comparator's type assertion, otherwise method panics.
func (tree *Tree) Put(key interface{}, value interface{}) { func (tree *Tree) Put(key interface{}, value interface{}) {
insertedNode := &Node{key: key, value: value, color: RED} insertedNode := &node{key: key, value: value, color: red}
if tree.root == nil { if tree.root == nil {
tree.root = insertedNode tree.root = insertedNode
} else { } else {
@ -114,7 +114,7 @@ func (tree *Tree) Get(key interface{}) (interface{}, bool) {
// Remove the node from the tree by key. // Remove the node from the tree by key.
// Key should adhere to the comparator's type assertion, otherwise method panics. // Key should adhere to the comparator's type assertion, otherwise method panics.
func (tree *Tree) Remove(key interface{}) { func (tree *Tree) Remove(key interface{}) {
var child *Node var child *node
node := tree.lookup(key) node := tree.lookup(key)
if node == nil { if node == nil {
return return
@ -131,13 +131,13 @@ func (tree *Tree) Remove(key interface{}) {
} else { } else {
child = node.right child = node.right
} }
if node.color == BLACK { if node.color == black {
node.color = color(child) node.color = nodeColor(child)
tree.deleteCase1(node) tree.deleteCase1(node)
} }
tree.replaceNode(node, child) tree.replaceNode(node, child)
if node.parent == nil && child != nil { if node.parent == nil && child != nil {
child.color = BLACK child.color = black
} }
} }
tree.size -= 1 tree.size -= 1
@ -161,11 +161,11 @@ func (tree *Tree) String() string {
return str return str
} }
func (node *Node) String() string { func (node *node) String() string {
return fmt.Sprintf("%v", node.key) return fmt.Sprintf("%v", node.key)
} }
func output(node *Node, prefix string, isTail bool, str *string) { func output(node *node, prefix string, isTail bool, str *string) {
if node.right != nil { if node.right != nil {
newPrefix := prefix newPrefix := prefix
if isTail { if isTail {
@ -193,7 +193,7 @@ func output(node *Node, prefix string, isTail bool, str *string) {
} }
} }
func (tree *Tree) lookup(key interface{}) *Node { func (tree *Tree) lookup(key interface{}) *node {
node := tree.root node := tree.root
for node != nil { for node != nil {
compare := tree.comparator(key, node.key) compare := tree.comparator(key, node.key)
@ -209,21 +209,21 @@ func (tree *Tree) lookup(key interface{}) *Node {
return nil return nil
} }
func (node *Node) grandparent() *Node { func (node *node) grandparent() *node {
if node != nil && node.parent != nil { if node != nil && node.parent != nil {
return node.parent.parent return node.parent.parent
} }
return nil return nil
} }
func (node *Node) uncle() *Node { func (node *node) uncle() *node {
if node == nil || node.parent == nil || node.parent.parent == nil { if node == nil || node.parent == nil || node.parent.parent == nil {
return nil return nil
} }
return node.parent.sibling() return node.parent.sibling()
} }
func (node *Node) sibling() *Node { func (node *node) sibling() *node {
if node == nil || node.parent == nil { if node == nil || node.parent == nil {
return nil return nil
} }
@ -234,7 +234,7 @@ func (node *Node) sibling() *Node {
} }
} }
func (tree *Tree) rotateLeft(node *Node) { func (tree *Tree) rotateLeft(node *node) {
right := node.right right := node.right
tree.replaceNode(node, right) tree.replaceNode(node, right)
node.right = right.left node.right = right.left
@ -245,7 +245,7 @@ func (tree *Tree) rotateLeft(node *Node) {
node.parent = right node.parent = right
} }
func (tree *Tree) rotateRight(node *Node) { func (tree *Tree) rotateRight(node *node) {
left := node.left left := node.left
tree.replaceNode(node, left) tree.replaceNode(node, left)
node.left = left.right node.left = left.right
@ -256,7 +256,7 @@ func (tree *Tree) rotateRight(node *Node) {
node.parent = left node.parent = left
} }
func (tree *Tree) replaceNode(old *Node, new *Node) { func (tree *Tree) replaceNode(old *node, new *node) {
if old.parent == nil { if old.parent == nil {
tree.root = new tree.root = new
} else { } else {
@ -271,34 +271,34 @@ func (tree *Tree) replaceNode(old *Node, new *Node) {
} }
} }
func (tree *Tree) insertCase1(node *Node) { func (tree *Tree) insertCase1(node *node) {
if node.parent == nil { if node.parent == nil {
node.color = BLACK node.color = black
} else { } else {
tree.insertCase2(node) tree.insertCase2(node)
} }
} }
func (tree *Tree) insertCase2(node *Node) { func (tree *Tree) insertCase2(node *node) {
if color(node.parent) == BLACK { if nodeColor(node.parent) == black {
return return
} }
tree.insertCase3(node) tree.insertCase3(node)
} }
func (tree *Tree) insertCase3(node *Node) { func (tree *Tree) insertCase3(node *node) {
uncle := node.uncle() uncle := node.uncle()
if color(uncle) == RED { if nodeColor(uncle) == red {
node.parent.color = BLACK node.parent.color = black
uncle.color = BLACK uncle.color = black
node.grandparent().color = RED node.grandparent().color = red
tree.insertCase1(node.grandparent()) tree.insertCase1(node.grandparent())
} else { } else {
tree.insertCase4(node) tree.insertCase4(node)
} }
} }
func (tree *Tree) insertCase4(node *Node) { func (tree *Tree) insertCase4(node *node) {
grandparent := node.grandparent() grandparent := node.grandparent()
if node == node.parent.right && node.parent == grandparent.left { if node == node.parent.right && node.parent == grandparent.left {
tree.rotateLeft(node.parent) tree.rotateLeft(node.parent)
@ -310,10 +310,10 @@ func (tree *Tree) insertCase4(node *Node) {
tree.insertCase5(node) tree.insertCase5(node)
} }
func (tree *Tree) insertCase5(node *Node) { func (tree *Tree) insertCase5(node *node) {
node.parent.color = BLACK node.parent.color = black
grandparent := node.grandparent() grandparent := node.grandparent()
grandparent.color = RED grandparent.color = red
if node == node.parent.left && node.parent == grandparent.left { if node == node.parent.left && node.parent == grandparent.left {
tree.rotateRight(grandparent) tree.rotateRight(grandparent)
} else if node == node.parent.right && node.parent == grandparent.right { } else if node == node.parent.right && node.parent == grandparent.right {
@ -321,7 +321,7 @@ func (tree *Tree) insertCase5(node *Node) {
} }
} }
func (node *Node) maximumNode() *Node { func (node *node) maximumNode() *node {
if node == nil { if node == nil {
return nil return nil
} }
@ -331,7 +331,7 @@ func (node *Node) maximumNode() *Node {
return node return node
} }
func (tree *Tree) deleteCase1(node *Node) { func (tree *Tree) deleteCase1(node *node) {
if node.parent == nil { if node.parent == nil {
return return
} else { } else {
@ -339,11 +339,11 @@ func (tree *Tree) deleteCase1(node *Node) {
} }
} }
func (tree *Tree) deleteCase2(node *Node) { func (tree *Tree) deleteCase2(node *node) {
sibling := node.sibling() sibling := node.sibling()
if color(sibling) == RED { if nodeColor(sibling) == red {
node.parent.color = RED node.parent.color = red
sibling.color = BLACK sibling.color = black
if node == node.parent.left { if node == node.parent.left {
tree.rotateLeft(node.parent) tree.rotateLeft(node.parent)
} else { } else {
@ -353,68 +353,68 @@ func (tree *Tree) deleteCase2(node *Node) {
tree.deleteCase3(node) tree.deleteCase3(node)
} }
func (tree *Tree) deleteCase3(node *Node) { func (tree *Tree) deleteCase3(node *node) {
sibling := node.sibling() sibling := node.sibling()
if color(node.parent) == BLACK && if nodeColor(node.parent) == black &&
color(sibling) == BLACK && nodeColor(sibling) == black &&
color(sibling.left) == BLACK && nodeColor(sibling.left) == black &&
color(sibling.right) == BLACK { nodeColor(sibling.right) == black {
sibling.color = RED sibling.color = red
tree.deleteCase1(node.parent) tree.deleteCase1(node.parent)
} else { } else {
tree.deleteCase4(node) tree.deleteCase4(node)
} }
} }
func (tree *Tree) deleteCase4(node *Node) { func (tree *Tree) deleteCase4(node *node) {
sibling := node.sibling() sibling := node.sibling()
if color(node.parent) == RED && if nodeColor(node.parent) == red &&
color(sibling) == BLACK && nodeColor(sibling) == black &&
color(sibling.left) == BLACK && nodeColor(sibling.left) == black &&
color(sibling.right) == BLACK { nodeColor(sibling.right) == black {
sibling.color = RED sibling.color = red
node.parent.color = BLACK node.parent.color = black
} else { } else {
tree.deleteCase5(node) tree.deleteCase5(node)
} }
} }
func (tree *Tree) deleteCase5(node *Node) { func (tree *Tree) deleteCase5(node *node) {
sibling := node.sibling() sibling := node.sibling()
if node == node.parent.left && if node == node.parent.left &&
color(sibling) == BLACK && nodeColor(sibling) == black &&
color(sibling.left) == RED && nodeColor(sibling.left) == red &&
color(sibling.right) == BLACK { nodeColor(sibling.right) == black {
sibling.color = RED sibling.color = red
sibling.left.color = BLACK sibling.left.color = black
tree.rotateRight(sibling) tree.rotateRight(sibling)
} else if node == node.parent.right && } else if node == node.parent.right &&
color(sibling) == BLACK && nodeColor(sibling) == black &&
color(sibling.right) == RED && nodeColor(sibling.right) == red &&
color(sibling.left) == BLACK { nodeColor(sibling.left) == black {
sibling.color = RED sibling.color = red
sibling.right.color = BLACK sibling.right.color = black
tree.rotateLeft(sibling) tree.rotateLeft(sibling)
} }
tree.deleteCase6(node) tree.deleteCase6(node)
} }
func (tree *Tree) deleteCase6(node *Node) { func (tree *Tree) deleteCase6(node *node) {
sibling := node.sibling() sibling := node.sibling()
sibling.color = color(node.parent) sibling.color = nodeColor(node.parent)
node.parent.color = BLACK node.parent.color = black
if node == node.parent.left && color(sibling.right) == RED { if node == node.parent.left && nodeColor(sibling.right) == red {
sibling.right.color = BLACK sibling.right.color = black
tree.rotateLeft(node.parent) tree.rotateLeft(node.parent)
} else if color(sibling.left) == RED { } else if nodeColor(sibling.left) == red {
sibling.left.color = BLACK sibling.left.color = black
tree.rotateRight(node.parent) tree.rotateRight(node.parent)
} }
} }
func color(node *Node) Color { func nodeColor(node *node) color {
if node == nil { if node == nil {
return BLACK return black
} }
return node.color return node.color
} }