structure/avl/avl.go

package avl

import (
	"github.com/davecgh/go-spew/spew"

	"github.com/emirpasic/gods/utils"
)

type Node struct {
	children [2]*Node
	parent   *Node
	height   int
	value    interface{}
}

func (n *Node) String() string {
	if n == nil {
		return "nil"
	}

	p := "nil"
	if n.parent != nil {
		p = spew.Sprint(n.parent.value)
	}
	return spew.Sprint(n.value) + "(" + p + "|" + spew.Sprint(n.height) + ")"
}

type Tree struct {
	root       *Node
	size       int
	comparator utils.Comparator
}

func New(comparator utils.Comparator) *Tree {
	if m == nil {
		m = make(map[int]int)
	}
	return &Tree{comparator: comparator}
}

func (avl *Tree) String() string {
	if avl.size == 0 {
		return ""
	}
	str := "AVLTree\n"
	output(avl.root, "", true, &str)

	return str
}

func (avl *Tree) Iterator() *Iterator {
	return initIterator(avl)
}

func (avl *Tree) Size() int {
	return avl.size
}

func (avl *Tree) Remove(key interface{}) *Node {

	if n, ok := avl.GetNode(key); ok {

		avl.size--
		if avl.size == 0 {
			avl.root = nil
			return n
		}

		left := getHeight(n.children[0])
		right := getHeight(n.children[1])

		if left == -1 && right == -1 {
			p := n.parent
			p.children[getRelationship(n)] = nil
			avl.fixRemoveHeight(p)
			return n
		}

		var cur *Node
		if left > right {
			cur = n.children[0]
			for cur.children[1] != nil {
				cur = cur.children[1]
			}

			cleft := cur.children[0]
			cur.parent.children[getRelationship(cur)] = cleft
			if cleft != nil {
				cleft.parent = cur.parent
			}

		} else {
			cur = n.children[1]
			for cur.children[0] != nil {
				cur = cur.children[0]
			}

			cright := cur.children[1]
			cur.parent.children[getRelationship(cur)] = cright

			if cright != nil {
				cright.parent = cur.parent
			}
		}

		cparent := cur.parent
		// 修改为interface 交换
		n.value, cur.value = cur.value, n.value

		// 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
		if cparent == n {
			avl.fixRemoveHeight(n)
		} else {
			avl.fixRemoveHeight(cparent)
		}

		return cur
	}

	return nil
}

// Values 返回先序遍历的值
func (avl *Tree) Values() []interface{} {
	mszie := 0
	if avl.root != nil {
		mszie = avl.size
	}
	result := make([]interface{}, 0, mszie)
	avl.Traversal(func(v interface{}) {
		result = append(result, v)
	}, DLR)
	return result
}

func (avl *Tree) Get(key interface{}) (interface{}, bool) {
	n, ok := avl.GetNode(key)
	if ok {
		return n.value, true
	}
	return n, false
}

func (avl *Tree) GetRange(min, max interface{}) []interface{} {
	return nil
}

func (avl *Tree) GetAround(key interface{}) (result [3]interface{}) {
	an := avl.GetAroundNode(key)
	for i, n := range an {
		if n != nil {
			result[i] = n.value
		}
	}
	return
}

func (avl *Tree) GetAroundNode(value interface{}) (result [3]*Node) {
	if cur, ok := avl.GetNode(value); ok {

		var iter *Iterator

		iter = NewIterator(cur)
		iter.curPushPrevStack(iter.up)
		iter.up = iter.getPrevUp(iter.up)

		if v, ok := iter.tstack.Pop(); ok {
			result[0] = v.(*Node)
			// iter.curPushPrevStack(iter.cur)
		} else {
			result[0] = iter.up
		}

		iter = NewIterator(cur)
		iter.curPushNextStack(iter.up)
		iter.up = iter.getNextUp(iter.up)

		if v, ok := iter.tstack.Pop(); ok {
			result[2] = v.(*Node)
			// iter.curPushNextStack(iter.cur)
		} else {
			result[2] = iter.up
		}

		result[1] = cur
	}
	return
}
func (avl *Tree) GetNode(value interface{}) (*Node, bool) {

	for n := avl.root; n != nil; {
		switch c := avl.comparator(value, n.value); c {
		case -1:
			n = n.children[0]
		case 1:
			n = n.children[1]
		case 0:
			return n, true
		default:
			panic("Get comparator only is allowed in -1, 0, 1")
		}
	}
	return nil, false
}

func (avl *Tree) Put(value interface{}) {
	avl.size++
	node := &Node{value: value}
	if avl.size == 1 {
		avl.root = node
		return
	}

	cur := avl.root
	parent := cur.parent
	child := -1

	for {

		if cur == nil {
			parent.children[child] = node
			node.parent = parent
			if node.parent.height == 0 {
				avl.fixPutHeight(node.parent)
			}
			return
		}

		parent = cur
		c := avl.comparator(value, cur.value)
		child = (c + 2) / 2
		cur = cur.children[child]
	}
}

func (avl *Tree) debugString() string {
	if avl.size == 0 {
		return ""
	}
	str := "AVLTree\n"
	outputfordebug(avl.root, "", true, &str)
	return str
}

type TraversalMethod int

const (
	_ TraversalMethod = iota
	//DLR 前序遍历
	DLR
	//LDR 中序遍历
	LDR
	//LRD 后序遍历
	LRD
)

// Traversal 遍历的方法
func (avl *Tree) Traversal(every func(v interface{}), traversalMethod ...interface{}) {
	if avl.root == nil {
		return
	}

	method := LDR
	if len(traversalMethod) != 0 {
		method = traversalMethod[0].(TraversalMethod)
	}

	switch method {
	case DLR:
		var traverasl func(cur *Node)
		traverasl = func(cur *Node) {
			if cur == nil {
				return
			}
			traverasl(cur.children[0])
			every(cur.value)
			traverasl(cur.children[1])
		}
		traverasl(avl.root)
	case LRD:
		var traverasl func(cur *Node)
		traverasl = func(cur *Node) {
			if cur == nil {
				return
			}
			traverasl(cur.children[1])
			every(cur.value)
			traverasl(cur.children[0])
		}
		traverasl(avl.root)
	case LDR:
		var traverasl func(cur *Node)
		traverasl = func(cur *Node) {
			if cur == nil {
				return
			}
			every(cur.value)
			traverasl(cur.children[0])
			traverasl(cur.children[1])
		}
		traverasl(avl.root)
	}
	return
}

func (avl *Tree) lrrotate(cur *Node) {

	const l = 1
	const r = 0

	movparent := cur.children[l]
	mov := movparent.children[r]

	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	if mov.children[l] != nil {
		movparent.children[r] = mov.children[l]
		movparent.children[r].parent = movparent
		//movparent.children[r].child = l
	} else {
		movparent.children[r] = nil
	}

	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
		//mov.children[l].child = l
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	cur.children[r] = mov
	mov.parent = cur

	// movparent.size = getChildrenSumSize(movparent) + 1
	// mov.size = getChildrenSumSize(mov) + 1
	// cur.size = getChildrenSumSize(cur) + 1

	mov.height = getMaxChildrenHeight(mov) + 1
	movparent.height = getMaxChildrenHeight(movparent) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func (avl *Tree) rlrotate(cur *Node) {

	const l = 0
	const r = 1

	movparent := cur.children[l]
	mov := movparent.children[r]

	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	if mov.children[l] != nil {
		movparent.children[r] = mov.children[l]
		movparent.children[r].parent = movparent
	} else {
		movparent.children[r] = nil
	}

	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	cur.children[r] = mov
	mov.parent = cur

	// movparent.size = getChildrenSumSize(movparent) + 1
	// mov.size = getChildrenSumSize(mov) + 1
	// cur.size = getChildrenSumSize(cur) + 1

	mov.height = getMaxChildrenHeight(mov) + 1
	movparent.height = getMaxChildrenHeight(movparent) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func (avl *Tree) rrotateex(cur *Node) {

	const l = 0
	const r = 1
	// 1 right 0 left
	mov := cur.children[l]
	if mov == nil {
		return
	}
	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	//  mov.children[l]不可能为nil
	cur.children[l] = mov.children[l]
	if mov.children[l] != nil {
		mov.children[l].parent = cur
	}

	// 解决mov节点孩子转移的问题
	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	// 连接转移后的节点 由于mov只是与cur交换值,parent不变
	cur.children[r] = mov

	mov.height = getMaxChildrenHeight(mov) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func (avl *Tree) rrotate(cur *Node) {

	const l = 0
	const r = 1
	// 1 right 0 left
	mov := cur.children[l]

	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	//  mov.children[l]不可能为nil
	mov.children[l].parent = cur
	cur.children[l] = mov.children[l]

	// 解决mov节点孩子转移的问题
	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	// 连接转移后的节点 由于mov只是与cur交换值,parent不变
	cur.children[r] = mov

	// mov.size = getChildrenSumSize(mov) + 1
	// cur.size = getChildrenSumSize(cur) + 1

	mov.height = getMaxChildrenHeight(mov) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func (avl *Tree) lrotateex(cur *Node) {

	const l = 1
	const r = 0

	mov := cur.children[l]
	if mov == nil {
		return
	}
	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	// 不可能为nil
	cur.children[l] = mov.children[l]
	if mov.children[l] != nil {
		mov.children[l].parent = cur
	}

	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	cur.children[r] = mov

	// mov.size = getChildrenSumSize(mov) + 1
	// cur.size = getChildrenSumSize(cur) + 1

	mov.height = getMaxChildrenHeight(mov) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func (avl *Tree) lrotate(cur *Node) {

	const l = 1
	const r = 0

	mov := cur.children[l]

	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移

	// 不可能为nil
	mov.children[l].parent = cur
	cur.children[l] = mov.children[l]

	if mov.children[r] != nil {
		mov.children[l] = mov.children[r]
	} else {
		mov.children[l] = nil
	}

	if cur.children[r] != nil {
		mov.children[r] = cur.children[r]
		mov.children[r].parent = mov
	} else {
		mov.children[r] = nil
	}

	cur.children[r] = mov

	// mov.size = getChildrenSumSize(mov) + 1
	// cur.size = getChildrenSumSize(cur) + 1

	mov.height = getMaxChildrenHeight(mov) + 1
	cur.height = getMaxChildrenHeight(cur) + 1
}

func getMaxAndChildrenHeight(cur *Node) (h1, h2, maxh int) {
	h1 = getHeight(cur.children[0])
	h2 = getHeight(cur.children[1])
	if h1 > h2 {
		maxh = h1
	} else {
		maxh = h2
	}

	return
}

func getMaxChildrenHeight(cur *Node) int {
	h1 := getHeight(cur.children[0])
	h2 := getHeight(cur.children[1])
	if h1 > h2 {
		return h1
	}
	return h2
}

func getHeight(cur *Node) int {
	if cur == nil {
		return -1
	}
	return cur.height
}

func abs(n int) int {
	y := n >> 31
	return (n ^ y) - y
}

func (avl *Tree) fixRemoveHeight(cur *Node) {
	for {

		lefth, rigthh, lrmax := getMaxAndChildrenHeight(cur)

		// 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
		isBreak := false
		if cur.height == lrmax+1 {
			isBreak = true
		} else {
			cur.height = lrmax + 1
		}

		// 计算高度的差值 绝对值大于2的时候需要旋转
		diff := lefth - rigthh
		if diff < -1 {
			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
			if getHeight(r.children[0]) > getHeight(r.children[1]) {
				avl.lrrotate(cur)
			} else {
				avl.lrotate(cur)
			}
		} else if diff > 1 {
			l := cur.children[0]
			if getHeight(l.children[1]) > getHeight(l.children[0]) {
				avl.rlrotate(cur)
			} else {
				avl.rrotate(cur)
			}
		} else {
			if isBreak {
				return
			}
		}

		if cur.parent == nil {
			return
		}

		cur = cur.parent
	}

}

var m map[int]int

func (avl *Tree) fixPutHeight(cur *Node) {

	for {

		lefth := getHeight(cur.children[0])
		rigthh := getHeight(cur.children[1])

		// 计算高度的差值 绝对值大于2的时候需要旋转
		diff := lefth - rigthh
		if diff < -1 {
			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
			if getHeight(r.children[0]) > getHeight(r.children[1]) {
				avl.lrrotate(cur)
			} else {
				avl.lrotate(cur)
			}
		} else if diff > 1 {
			l := cur.children[0]
			if getHeight(l.children[1]) > getHeight(l.children[0]) {
				avl.rlrotate(cur)
			} else {
				avl.rrotate(cur)
			}

		} else {
			// 选择一个child的最大高度 + 1为 高度
			if lefth > rigthh {
				cur.height = lefth + 1
			} else {
				cur.height = rigthh + 1
			}
		}

		if cur.parent == nil || cur.height < cur.parent.height {
			return
		}
		cur = cur.parent
	}
}

func output(node *Node, prefix string, isTail bool, str *string) {

	if node.children[1] != nil {
		newPrefix := prefix
		if isTail {
			newPrefix += "│   "
		} else {
			newPrefix += "    "
		}
		output(node.children[1], newPrefix, false, str)
	}
	*str += prefix
	if isTail {
		*str += "└── "
	} else {
		*str += "┌── "
	}

	*str += spew.Sprint(node.value) + "\n"

	if node.children[0] != nil {
		newPrefix := prefix
		if isTail {
			newPrefix += "    "
		} else {
			newPrefix += "│   "
		}
		output(node.children[0], newPrefix, true, str)
	}

}

func outputfordebug(node *Node, prefix string, isTail bool, str *string) {

	if node.children[1] != nil {
		newPrefix := prefix
		if isTail {
			newPrefix += "│   "
		} else {
			newPrefix += "    "
		}
		outputfordebug(node.children[1], newPrefix, false, str)
	}
	*str += prefix
	if isTail {
		*str += "└── "
	} else {
		*str += "┌── "
	}

	suffix := "("
	parentv := ""
	if node.parent == nil {
		parentv = "nil"
	} else {
		parentv = spew.Sprint(node.parent.value)
	}
	suffix += parentv + "|" + spew.Sprint(node.height) + ")"
	*str += spew.Sprint(node.value) + suffix + "\n"

	if node.children[0] != nil {
		newPrefix := prefix
		if isTail {
			newPrefix += "    "
		} else {
			newPrefix += "│   "
		}
		outputfordebug(node.children[0], newPrefix, true, str)
	}
}