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|
package main
import (
"fmt"
)
var nodeCnt int
type Node struct {
val int
left, right *Node
h int
}
func max(i, j int) int {
if i > j {
return i
}
return j
}
func min(i, j int) int {
if i < j {
return i
}
return j
}
func (node *Node) height() int {
if node == nil {
return 0
}
return node.h
}
// 对节点y进行向右旋转操作，返回旋转后新的根节点x
// y x
// / \ / \
// x T4 向右旋转 (y) z y
// / \ - - - - - - - -> / \ / \
// z T3 T1 T2 T3 T4
// / \
// T1 T2
func adjustLeft(y *Node) *Node {
if y == nil {
panic("invalid node")
}
var x = y.left
y.left = x.right
x.right = y
y.h = max(y.left.height(), y.right.height()) + 1
x.h = max(x.left.height(), x.right.height()) + 1
return x
//var leftChild = this.left
//this.left = this.right
//leftChild.right = this
//this.h = max(this.left.height(), this.right.height()) + 1
//leftChild.h = max(leftChild.left.height(), leftChild.right.height()) + 1
//return leftChild
}
/*
y => x
a x y
b c xxxxxx
e d
*/
// right 重，左旋转
func adjustRight(y *Node) *Node {
if y == nil {
panic("invalid node")
}
var x = y.right
// x >= y
y.right = x.left
x.left = y
y.h = max(y.left.height(), y.right.height()) + 1
x.h = max(x.left.height(), x.right.height()) + 1
return x
}
// left 重， left.right 重
func adjustLeftRight(node *Node) *Node {
//左子树的右节点
node.left = adjustRight(node.left)
// left left rotation
return adjustLeft(node)
}
// right 重，并且 right.left 重
func adjustRightLeft(node *Node) *Node {
node.right = adjustLeft(node.right)
return adjustRight(node)
}
func insertNode(node *Node, val int) *Node {
if node == nil {
nodeCnt++
return &Node{val: val, h: 1}
}
switch {
case node.val < val:
// current < val , to right find
node.right = insertNode(node.right, val)
// 插入 右边节点，只能是 height(right) >= height(left)
if node.right.height()-node.left.height() == 2 {
// adjust right
if val > node.right.val {
// right 重，right.right也重
node = adjustRight(node)
} else {
// right 重，right.left重
node = adjustRightLeft(node)
}
}
case node.val > val:
// 去插入到左边节点
node.left = insertNode(node.left, val)
if node.left.height()-node.right.height() == 2 {
// 判断 left.val < val
if node.left.val > val {
// left重，left.left也重， 处理 ll
node = adjustLeft(node)
} else {
//left, left.right重
node = adjustLeftRight(node)
}
}
default:
//log.Println("exists")
}
node.h = max(node.left.height(), node.right.height()) + 1
return node
}
func findMinNode(node *Node) *Node {
if node == nil {
return nil
}
for node.left != nil {
node = node.left
}
return node
}
func findMaxNode(node *Node) *Node {
if node == nil {
return nil
}
for node.right != nil {
node = node.right
}
return node
}
// >= val => 天花板，下边界
func findFloorNode(node *Node, val int) *Node {
Loop:
for node != nil {
if node.val == val {
//return node
break Loop
} else if node.val < val {
// to right
node = node.right
} else {
//to left, if left is nil , return current Node
//node = node.right
left := findFloorNode(node.left, val)
if left != nil && left.val < node.val {
node = left
}
break Loop
// left is small
}
}
return node
}
// <= val 的最大节点
func findCeilNode(node *Node, val int) *Node {
// 早到 比 val 小的
if node == nil {
return nil
}
find:
for node != nil {
if node.val == val {
break find
} else if node.val > val {
// 比他大 ， 左边 的 可能也比他大
node = node.left
} else {
// node.val < val , to right find <= val first
var s = findCeilNode(node.right, val)
if s != nil && s.val > node.val {
node = s
}
break find
}
}
return node
}
func adjustNode(node *Node) *Node {
// adjust node
switch node.left.height() - node.right.height() {
case 2:
// left 重
//var left = node.left
if node.left.height() > node.right.height() {
node = adjustLeft(node)
} else {
node = adjustLeftRight(node)
}
case -2:
if node.right.right.height() > node.right.left.height() {
// right right 重
node = adjustRight(node)
} else {
node = adjustRightLeft(node)
}
}
return node
}
func deleteNode(node *Node, val int) *Node {
if node == nil {
return nil
}
if node.val < val {
node.right = deleteNode(node.right, val)
} else if node.val > val {
// to left delete
node.left = deleteNode(node.left, val)
} else {
// delete current
nodeCnt--
if node.left == nil {
if node.right == nil {
//delete one
node = nil
} else {
// return node.right
node = node.right
}
} else {
if node.right == nil {
//node.left != nil
node = node.left
} else {
// node.left != nil node.right !=nil
//前驱节点
var nextNode = findMinNode(node.right)
node.val = nextNode.val
//委托 删除 minNode ， 这边不好删除，直接 取巧 ，覆盖值即可
node.right = deleteNode(node.right, nextNode.val)
}
}
}
if node != nil {
//跳转高度
node.h = max(node.left.height(), node.right.height()) + 1
node = adjustNode(node)
}
return node
}
//func rightRotationNode(node *Node) *Node {
// var right = node.right
// node.right = node.left
// node
//}
func ascPrint(node *Node) {
if node == nil {
return
}
ascPrint(node.left)
fmt.Printf("%v,", node.val)
ascPrint(node.right)
}
func main() {
var node *Node
//node = insertNode(node,2)
//fmt.Println(node)
//
node = insertNode(node, 1)
node = insertNode(node, 5)
node = insertNode(node, 9)
node = insertNode(node, 1)
node = insertNode(node, 5)
//node = insertNode(node,2)
node = insertNode(node, 9)
//node = deleteNode(node,1)
ascPrint(node)
fmt.Println()
node = deleteNode(node, 4)
ascPrint(node)
fmt.Println()
// <= 1
fmt.Println(findCeilNode(node, 5-3).val)
//q := make([]*Node, 0)
//q = append(q, node)
//for len(q) > 0 {
// var n = len(q)
// for i := 0; i < n; i++ {
// var res = q[0]
// q = q[1:]
// log.Printf("%+v,", res.val)
// if res.left != nil {
// q = append(q, res.left)
// }
// if res.right != nil {
// q = append(q, res.right)
// }
// }
// log.Println("----------------------------------------------")
//}
//fmt.Println("node count = ",nodeCnt)
}
|
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