146 lines
2.6 KiB
Go
146 lines
2.6 KiB
Go
package _4_tree
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type BST struct {
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*BinaryTree
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//比对函数，0:v==nodeV,正数:v>nodeV,负数:v<nodeV
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compareFunc func(v, nodeV interface{}) int
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}
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func NewBST(rootV interface{}, compareFunc func(v, nodeV interface{}) int) *BST {
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if nil == compareFunc {
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return nil
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}
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return &BST{BinaryTree: NewBinaryTree(rootV), compareFunc: compareFunc}
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}
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func (this *BST) Find(v interface{}) *Node {
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p := this.root
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for nil != p {
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compareResult := this.compareFunc(v, p.data)
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if compareResult == 0 {
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return p
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} else if compareResult > 0 { //v > nodeV
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p = p.right
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} else { //v < nodeV
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p = p.left
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}
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}
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return nil
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}
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func (this *BST) Insert(v interface{}) bool {
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p := this.root
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for nil != p {
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compareResult := this.compareFunc(v, p.data)
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if compareResult == 0 {
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return false
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} else if compareResult > 0 {
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if nil == p.right {
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p.right = NewNode(v)
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break
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}
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p = p.right
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} else {
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if nil == p.left {
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p.left = NewNode(v)
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break
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}
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p = p.left
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}
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}
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return true
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}
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func (this *BST) Delete(v interface{}) bool {
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var pp *Node = nil
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p := this.root
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deleteLeft := false
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for nil != p {
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compareResult := this.compareFunc(v, p.data)
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if compareResult > 0 {
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pp = p
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p = p.right
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deleteLeft = false
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} else if compareResult < 0 {
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pp = p
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p = p.left
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deleteLeft = true
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} else {
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break
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}
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}
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if nil == p { //需要删除的节点不存在
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return false
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} else if nil == p.left && nil == p.right { //删除的是一个叶子节点
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if nil != pp {
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if deleteLeft {
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pp.left = nil
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} else {
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pp.right = nil
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}
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} else { //根节点
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this.root = nil
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}
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} else if nil != p.right { //删除的是一个有右孩子，不一定有左孩子的节点
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//找到p节点右孩子的最小节点
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pq := p
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q := p.right //向右走一步
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fromRight := true
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for nil != q.left { //向左走到底
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pq = q
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q = q.left
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fromRight = false
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}
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if fromRight {
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pq.right = nil
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} else {
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pq.left = nil
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}
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q.left = p.left
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q.right = p.right
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if nil == pp { //根节点被删除
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this.root = q
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} else {
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if deleteLeft {
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pq.left = q
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} else {
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pq.right = q
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}
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}
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} else { //删除的是一个只有左孩子的节点
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if nil != pp {
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if deleteLeft {
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pp.left = p.left
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} else {
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pp.right = p.left
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}
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} else {
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if deleteLeft {
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this.root = p.left
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} else {
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this.root = p.left
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}
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}
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}
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return true
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}
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func (this *BST) Min() *Node {
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p := this.root
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for nil != p.left {
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p = p.left
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}
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return p
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}
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func (this *BST) Max() *Node {
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p := this.root
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for nil != p.right {
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p = p.right
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}
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return p
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}
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