558 lines
10 KiB
Go
558 lines
10 KiB
Go
package bstree
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import (
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"github.com/davecgh/go-spew/spew"
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"github.com/emirpasic/gods/utils"
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)
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type Node struct {
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children [2]*Node
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parent *Node
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height int
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child int
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value interface{}
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}
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func (n *Node) String() string {
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if n == nil {
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return "nil"
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}
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p := "nil"
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if n.parent != nil {
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p = spew.Sprint(n.parent.value)
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}
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return spew.Sprint(n.value) + "(" + p + "-" + spew.Sprint(n.child) + "|" + spew.Sprint(n.height) + ")"
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}
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type AVLTree struct {
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root *Node
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size int
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comparator utils.Comparator
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}
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func New(comparator utils.Comparator) *AVLTree {
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return &AVLTree{comparator: comparator}
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}
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func (avl *AVLTree) String() string {
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if avl.size == 0 {
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return ""
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}
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str := "AVLTree" + "\n"
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output(avl.root, "", true, &str)
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return str
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}
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func (avl *AVLTree) Remove(v interface{}) *Node {
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if n, ok := avl.GetNode(v); ok {
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avl.size--
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if avl.size == 0 {
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avl.root = nil
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return n
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}
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left := getHeight(n.children[0])
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right := getHeight(n.children[1])
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if left == -1 && right == -1 {
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p := n.parent
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p.children[n.child] = nil
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avl.fixRemoveHeight(p)
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return n
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}
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var cur *Node
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if left > right {
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cur = n.children[0]
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for cur.children[1] != nil {
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cur = cur.children[1]
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}
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cleft := cur.children[0]
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cur.parent.children[cur.child] = cleft
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if cleft != nil {
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cleft.child = cur.child
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cleft.parent = cur.parent
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}
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} else {
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cur = n.children[1]
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for cur.children[0] != nil {
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cur = cur.children[0]
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}
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cright := cur.children[1]
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cur.parent.children[cur.child] = cright
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if cright != nil {
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cright.child = cur.child
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cright.parent = cur.parent
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}
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}
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cparent := cur.parent
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avl.replace(n, cur)
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// 考虑到刚好替换的节点是 被替换节点的孩子节点的时候, 从自身修复高度
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if cparent == n {
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avl.fixRemoveHeight(cur)
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} else {
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avl.fixRemoveHeight(cparent)
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}
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return n
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}
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return nil
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}
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func (avl *AVLTree) Get(v interface{}) (interface{}, bool) {
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n, ok := avl.GetNode(v)
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if ok {
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return n.value, true
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}
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return n, false
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}
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func (avl *AVLTree) GetNode(v interface{}) (*Node, bool) {
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n := avl.root
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for n != nil {
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switch c := avl.comparator(v, n.value); c {
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case -1:
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n = n.children[0]
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case 1:
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n = n.children[1]
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case 0:
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return n, true
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default:
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panic("Get comparator only is allowed in -1, 0, 1")
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}
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}
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return nil, false
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}
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func (avl *AVLTree) Put(v interface{}) {
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avl.size++
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node := &Node{value: v}
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if avl.size == 1 {
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avl.root = node
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return
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}
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cur := avl.root
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parent := cur.parent
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child := -1
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for {
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if cur == nil {
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parent.children[child] = node
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node.parent = parent
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node.child = child
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if node.parent.height == 0 {
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avl.fixPutHeight(node.parent)
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}
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return
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}
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parent = cur
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c := avl.comparator(node.value, cur.value)
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if c > -1 { // right
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child = 1
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cur = cur.children[child]
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} else {
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child = 0
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cur = cur.children[child]
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}
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}
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}
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func (avl *AVLTree) replace(old *Node, newN *Node) {
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if old.parent == nil {
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setChild(newN, 0, old.children[0])
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setChild(newN, 1, old.children[1])
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newN.parent = nil
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newN.child = -1
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newN.height = old.height
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avl.root = newN
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} else {
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setChild(newN, 0, old.children[0])
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setChild(newN, 1, old.children[1])
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newN.parent = old.parent
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newN.child = old.child
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newN.height = old.height
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old.parent.children[old.child] = newN
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}
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}
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func setChild(p *Node, child int, node *Node) {
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p.children[child] = node
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if node != nil {
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node.child = child
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node.parent = p
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}
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}
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func setChildNotNil(p *Node, child int, node *Node) {
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p.children[child] = node
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node.child = child
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node.parent = p
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}
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func (avl *AVLTree) debugString() string {
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if avl.size == 0 {
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return ""
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}
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str := "AVLTree" + "\n"
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outputfordebug(avl.root, "", true, &str)
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return str
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}
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func (avl *AVLTree) TraversalBreadth() (result []interface{}) {
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var traverasl func(cur *Node)
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traverasl = func(cur *Node) {
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if cur == nil {
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return
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}
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result = append(result, cur.value)
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traverasl(cur.children[0])
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traverasl(cur.children[1])
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}
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traverasl(avl.root)
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return
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}
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func (avl *AVLTree) TraversalDepth(leftright int) (result []interface{}) {
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if leftright < 0 {
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var traverasl func(cur *Node)
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traverasl = func(cur *Node) {
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if cur == nil {
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return
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}
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traverasl(cur.children[0])
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result = append(result, cur.value)
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traverasl(cur.children[1])
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}
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traverasl(avl.root)
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} else {
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var traverasl func(cur *Node)
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traverasl = func(cur *Node) {
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if cur == nil {
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return
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}
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traverasl(cur.children[1])
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result = append(result, cur.value)
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traverasl(cur.children[0])
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}
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traverasl(avl.root)
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}
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return
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}
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func (avl *AVLTree) lrrotate(cur *Node) *Node {
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r := cur.children[1]
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rl := r.children[0]
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if cur.parent == nil {
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avl.root = rl
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rl.parent = nil
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} else {
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setChildNotNil(cur.parent, cur.child, rl)
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}
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rll := rl.children[0]
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rlr := rl.children[1]
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setChild(cur, 1, rll)
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setChild(r, 0, rlr)
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setChildNotNil(rl, 0, cur)
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setChildNotNil(rl, 1, r)
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cur.height = getMaxChildrenHeight(cur) + 1
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r.height = getMaxChildrenHeight(r) + 1
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rl.height = getMaxChildrenHeight(rl) + 1
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return rl
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}
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func (avl *AVLTree) rlrotate(cur *Node) *Node {
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l := cur.children[0]
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lr := l.children[1]
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if cur.parent == nil {
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avl.root = lr
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lr.parent = nil
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} else {
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setChildNotNil(cur.parent, cur.child, lr)
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}
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lrr := lr.children[1]
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lrl := lr.children[0]
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setChild(cur, 0, lrr)
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setChild(l, 1, lrl)
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setChildNotNil(lr, 1, cur)
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setChildNotNil(lr, 0, l)
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cur.height = getMaxChildrenHeight(cur) + 1
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l.height = getMaxChildrenHeight(l) + 1
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lr.height = getMaxChildrenHeight(lr) + 1
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return lr
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}
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func (avl *AVLTree) rrotate(cur *Node) *Node {
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l := cur.children[0]
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setChild(cur, 0, l.children[1])
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l.parent = cur.parent
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if cur.parent == nil {
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avl.root = l
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} else {
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cur.parent.children[cur.child] = l
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}
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l.child = cur.child
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setChildNotNil(l, 1, cur)
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// l.children[1] = cur
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// cur.child = 1
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// cur.parent = l
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cur.height = getMaxChildrenHeight(cur) + 1
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l.height = getMaxChildrenHeight(l) + 1
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return l // 返回前 替换为cur节点的节点, 有利余修复高度
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}
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func (avl *AVLTree) lrotate(cur *Node) *Node {
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r := cur.children[1]
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// 右左节点 链接 当前的右节点
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setChild(cur, 1, r.children[0])
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// 设置 需要旋转的节点到当前节点的 链条
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r.parent = cur.parent
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if cur.parent == nil {
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avl.root = r
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} else {
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cur.parent.children[cur.child] = r
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}
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r.child = cur.child
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// 当前节点旋转到 左边的 链条
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setChildNotNil(r, 0, cur)
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// r.children[0] = cur
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// cur.child = 0
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// cur.parent = r
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// 修复改动过的节点高度 先从低开始到高
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cur.height = getMaxChildrenHeight(cur) + 1
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r.height = getMaxChildrenHeight(r) + 1
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return r
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}
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func getMaxAndChildrenHeight(cur *Node) (h1, h2, maxh int) {
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h1 = getHeight(cur.children[0])
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h2 = getHeight(cur.children[1])
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if h1 > h2 {
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maxh = h1
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} else {
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maxh = h2
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}
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return
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}
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func getMaxChildrenHeight(cur *Node) int {
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h1 := getHeight(cur.children[0])
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h2 := getHeight(cur.children[1])
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if h1 > h2 {
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return h1
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}
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return h2
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}
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func getHeight(cur *Node) int {
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if cur == nil {
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return -1
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}
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return cur.height
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}
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func (avl *AVLTree) fixRemoveHeight(cur *Node) {
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for {
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lefth, rigthh, lrmax := getMaxAndChildrenHeight(cur)
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// 判断当前节点是否有变化, 如果没变化的时候, 不需要往上修复
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isBreak := false
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if cur.height == lrmax+1 {
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isBreak = true
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} else {
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cur.height = lrmax + 1
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}
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// 计算高度的差值 绝对值大于2的时候需要旋转
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diff := lefth - rigthh
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if diff < -1 {
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r := cur.children[1] // 根据左旋转的右边节点的子节点 左右高度选择旋转的方式
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if getHeight(r.children[0]) > getHeight(r.children[1]) {
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cur = avl.lrrotate(cur)
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} else {
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cur = avl.lrotate(cur)
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}
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} else if diff > 1 {
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l := cur.children[0]
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if getHeight(l.children[1]) > getHeight(l.children[0]) {
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cur = avl.rlrotate(cur)
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} else {
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cur = avl.rrotate(cur)
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}
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} else {
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if isBreak {
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return
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}
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}
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if cur.parent == nil {
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return
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}
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cur = cur.parent
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}
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}
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func (avl *AVLTree) fixPutHeight(cur *Node) {
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for {
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lefth := getHeight(cur.children[0])
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rigthh := getHeight(cur.children[1])
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// 计算高度的差值 绝对值大于2的时候需要旋转
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diff := lefth - rigthh
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if diff < -1 {
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r := cur.children[1] // 根据左旋转的右边节点的子节点 左右高度选择旋转的方式
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if getHeight(r.children[0]) > getHeight(r.children[1]) {
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cur = avl.lrrotate(cur)
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} else {
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cur = avl.lrotate(cur)
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}
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} else if diff > 1 {
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l := cur.children[0]
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if getHeight(l.children[1]) > getHeight(l.children[0]) {
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cur = avl.rlrotate(cur)
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} else {
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cur = avl.rrotate(cur)
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}
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} else {
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// 选择一个child的最大高度 + 1为 高度
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if lefth > rigthh {
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cur.height = lefth + 1
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} else {
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cur.height = rigthh + 1
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}
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}
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if cur.parent == nil || cur.height < cur.parent.height {
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return
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}
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cur = cur.parent
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}
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}
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func output(node *Node, prefix string, isTail bool, str *string) {
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if node.children[1] != nil {
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newPrefix := prefix
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if isTail {
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newPrefix += "│ "
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} else {
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newPrefix += " "
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}
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output(node.children[1], newPrefix, false, str)
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}
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*str += prefix
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if isTail {
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*str += "└── "
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} else {
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*str += "┌── "
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}
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*str += spew.Sprint(node.value) + "\n"
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if node.children[0] != nil {
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newPrefix := prefix
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if isTail {
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newPrefix += " "
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} else {
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newPrefix += "│ "
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}
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output(node.children[0], newPrefix, true, str)
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}
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}
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func outputfordebug(node *Node, prefix string, isTail bool, str *string) {
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if node.children[1] != nil {
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newPrefix := prefix
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if isTail {
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newPrefix += "│ "
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} else {
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newPrefix += " "
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}
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outputfordebug(node.children[1], newPrefix, false, str)
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}
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*str += prefix
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if isTail {
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*str += "└── "
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} else {
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*str += "┌── "
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}
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suffix := "("
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parentv := ""
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if node.parent == nil {
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parentv = "nil"
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} else {
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parentv = spew.Sprint(node.parent.value)
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}
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suffix += parentv + "-" + spew.Sprint(node.child) + "|" + spew.Sprint(node.height) + ")"
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*str += spew.Sprint(node.value) + suffix + "\n"
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if node.children[0] != nil {
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newPrefix := prefix
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if isTail {
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newPrefix += " "
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} else {
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newPrefix += "│ "
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}
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outputfordebug(node.children[0], newPrefix, true, str)
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}
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}
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