gf/container/gtree/gtree_avltree.go
2019-11-30 18:33:51 +08:00

787 lines
19 KiB
Go

// Copyright 2019 gf Author(https://github.com/gogf/gf). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.
package gtree
import (
"encoding/json"
"fmt"
"github.com/gogf/gf/util/gconv"
"github.com/gogf/gf/container/gvar"
"github.com/gogf/gf/internal/rwmutex"
)
// AVLTree holds elements of the AVL tree.
type AVLTree struct {
mu *rwmutex.RWMutex
root *AVLTreeNode
comparator func(v1, v2 interface{}) int
size int
}
// AVLTreeNode is a single element within the tree.
type AVLTreeNode struct {
Key interface{}
Value interface{}
parent *AVLTreeNode
children [2]*AVLTreeNode
b int8
}
// NewAVLTree instantiates an AVL tree with the custom key comparator.
// The parameter <safe> is used to specify whether using tree in concurrent-safety,
// which is false in default.
func NewAVLTree(comparator func(v1, v2 interface{}) int, safe ...bool) *AVLTree {
return &AVLTree{
mu: rwmutex.New(safe...),
comparator: comparator,
}
}
// NewAVLTreeFrom instantiates an AVL tree with the custom key comparator and data map.
// The parameter <safe> is used to specify whether using tree in concurrent-safety,
// which is false in default.
func NewAVLTreeFrom(comparator func(v1, v2 interface{}) int, data map[interface{}]interface{}, safe ...bool) *AVLTree {
tree := NewAVLTree(comparator, safe...)
for k, v := range data {
tree.put(k, v, nil, &tree.root)
}
return tree
}
// Clone returns a new tree with a copy of current tree.
func (tree *AVLTree) Clone(safe ...bool) *AVLTree {
newTree := NewAVLTree(tree.comparator, !tree.mu.IsSafe())
newTree.Sets(tree.Map())
return newTree
}
// Set inserts node into the tree.
func (tree *AVLTree) Set(key interface{}, value interface{}) {
tree.mu.Lock()
defer tree.mu.Unlock()
tree.put(key, value, nil, &tree.root)
}
// Sets batch sets key-values to the tree.
func (tree *AVLTree) Sets(data map[interface{}]interface{}) {
tree.mu.Lock()
defer tree.mu.Unlock()
for key, value := range data {
tree.put(key, value, nil, &tree.root)
}
}
// Search searches the tree with given <key>.
// Second return parameter <found> is true if key was found, otherwise false.
func (tree *AVLTree) Search(key interface{}) (value interface{}, found bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
if node, found := tree.doSearch(key); found {
return node.Value, true
}
return nil, false
}
// doSearch searches the tree with given <key>.
// Second return parameter <found> is true if key was found, otherwise false.
func (tree *AVLTree) doSearch(key interface{}) (node *AVLTreeNode, found bool) {
node = tree.root
for node != nil {
cmp := tree.comparator(key, node.Key)
switch {
case cmp == 0:
return node, true
case cmp < 0:
node = node.children[0]
case cmp > 0:
node = node.children[1]
}
}
return nil, false
}
// Get searches the node in the tree by <key> and returns its value or nil if key is not found in tree.
func (tree *AVLTree) Get(key interface{}) (value interface{}) {
value, _ = tree.Search(key)
return
}
// doSetWithLockCheck checks whether value of the key exists with mutex.Lock,
// if not exists, set value to the map with given <key>,
// or else just return the existing value.
//
// When setting value, if <value> is type of <func() interface {}>,
// it will be executed with mutex.Lock of the hash map,
// and its return value will be set to the map with <key>.
//
// It returns value with given <key>.
func (tree *AVLTree) doSetWithLockCheck(key interface{}, value interface{}) interface{} {
tree.mu.Lock()
defer tree.mu.Unlock()
if node, found := tree.doSearch(key); found {
return node.Value
}
if f, ok := value.(func() interface{}); ok {
value = f()
}
if value != nil {
tree.put(key, value, nil, &tree.root)
}
return value
}
// GetOrSet returns the value by key,
// or sets value with given <value> if it does not exist and then returns this value.
func (tree *AVLTree) GetOrSet(key interface{}, value interface{}) interface{} {
if v, ok := tree.Search(key); !ok {
return tree.doSetWithLockCheck(key, value)
} else {
return v
}
}
// GetOrSetFunc returns the value by key,
// or sets value with returned value of callback function <f> if it does not exist
// and then returns this value.
func (tree *AVLTree) GetOrSetFunc(key interface{}, f func() interface{}) interface{} {
if v, ok := tree.Search(key); !ok {
return tree.doSetWithLockCheck(key, f())
} else {
return v
}
}
// GetOrSetFuncLock returns the value by key,
// or sets value with returned value of callback function <f> if it does not exist
// and then returns this value.
//
// GetOrSetFuncLock differs with GetOrSetFunc function is that it executes function <f>
// with mutex.Lock of the hash map.
func (tree *AVLTree) GetOrSetFuncLock(key interface{}, f func() interface{}) interface{} {
if v, ok := tree.Search(key); !ok {
return tree.doSetWithLockCheck(key, f)
} else {
return v
}
}
// GetVar returns a gvar.Var with the value by given <key>.
// The returned gvar.Var is un-concurrent safe.
func (tree *AVLTree) GetVar(key interface{}) *gvar.Var {
return gvar.New(tree.Get(key))
}
// GetVarOrSet returns a gvar.Var with result from GetVarOrSet.
// The returned gvar.Var is un-concurrent safe.
func (tree *AVLTree) GetVarOrSet(key interface{}, value interface{}) *gvar.Var {
return gvar.New(tree.GetOrSet(key, value))
}
// GetVarOrSetFunc returns a gvar.Var with result from GetOrSetFunc.
// The returned gvar.Var is un-concurrent safe.
func (tree *AVLTree) GetVarOrSetFunc(key interface{}, f func() interface{}) *gvar.Var {
return gvar.New(tree.GetOrSetFunc(key, f))
}
// GetVarOrSetFuncLock returns a gvar.Var with result from GetOrSetFuncLock.
// The returned gvar.Var is un-concurrent safe.
func (tree *AVLTree) GetVarOrSetFuncLock(key interface{}, f func() interface{}) *gvar.Var {
return gvar.New(tree.GetOrSetFuncLock(key, f))
}
// SetIfNotExist sets <value> to the map if the <key> does not exist, and then returns true.
// It returns false if <key> exists, and <value> would be ignored.
func (tree *AVLTree) SetIfNotExist(key interface{}, value interface{}) bool {
if !tree.Contains(key) {
tree.doSetWithLockCheck(key, value)
return true
}
return false
}
// SetIfNotExistFunc sets value with return value of callback function <f>, and then returns true.
// It returns false if <key> exists, and <value> would be ignored.
func (tree *AVLTree) SetIfNotExistFunc(key interface{}, f func() interface{}) bool {
if !tree.Contains(key) {
tree.doSetWithLockCheck(key, f())
return true
}
return false
}
// SetIfNotExistFuncLock sets value with return value of callback function <f>, and then returns true.
// It returns false if <key> exists, and <value> would be ignored.
//
// SetIfNotExistFuncLock differs with SetIfNotExistFunc function is that
// it executes function <f> with mutex.Lock of the hash map.
func (tree *AVLTree) SetIfNotExistFuncLock(key interface{}, f func() interface{}) bool {
if !tree.Contains(key) {
tree.doSetWithLockCheck(key, f)
return true
}
return false
}
// Contains checks whether <key> exists in the tree.
func (tree *AVLTree) Contains(key interface{}) bool {
_, ok := tree.Search(key)
return ok
}
// Remove removes the node from the tree by key.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (tree *AVLTree) Remove(key interface{}) (value interface{}) {
tree.mu.Lock()
defer tree.mu.Unlock()
value, _ = tree.remove(key, &tree.root)
return
}
// Removes batch deletes values of the tree by <keys>.
func (tree *AVLTree) Removes(keys []interface{}) {
tree.mu.Lock()
defer tree.mu.Unlock()
for _, key := range keys {
tree.remove(key, &tree.root)
}
}
// IsEmpty returns true if tree does not contain any nodes.
func (tree *AVLTree) IsEmpty() bool {
return tree.Size() == 0
}
// Size returns number of nodes in the tree.
func (tree *AVLTree) Size() int {
tree.mu.RLock()
defer tree.mu.RUnlock()
return tree.size
}
// Keys returns all keys in asc order.
func (tree *AVLTree) Keys() []interface{} {
keys := make([]interface{}, tree.Size())
index := 0
tree.IteratorAsc(func(key, value interface{}) bool {
keys[index] = key
index++
return true
})
return keys
}
// Values returns all values in asc order based on the key.
func (tree *AVLTree) Values() []interface{} {
values := make([]interface{}, tree.Size())
index := 0
tree.IteratorAsc(func(key, value interface{}) bool {
values[index] = value
index++
return true
})
return values
}
// Left returns the minimum element of the AVL tree
// or nil if the tree is empty.
func (tree *AVLTree) Left() *AVLTreeNode {
tree.mu.RLock()
defer tree.mu.RUnlock()
node := tree.bottom(0)
if tree.mu.IsSafe() {
return &AVLTreeNode{
Key: node.Key,
Value: node.Value,
}
}
return node
}
// Right returns the maximum element of the AVL tree
// or nil if the tree is empty.
func (tree *AVLTree) Right() *AVLTreeNode {
tree.mu.RLock()
defer tree.mu.RUnlock()
node := tree.bottom(1)
if tree.mu.IsSafe() {
return &AVLTreeNode{
Key: node.Key,
Value: node.Value,
}
}
return node
}
// Floor Finds floor node of the input key, return the floor node or nil if no floor node is found.
// Second return parameter is true if floor was found, otherwise false.
//
// Floor node is defined as the largest node that is smaller than or equal to the given node.
// A floor node may not be found, either because the tree is empty, or because
// all nodes in the tree is larger than the given node.
//
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (tree *AVLTree) Floor(key interface{}) (floor *AVLTreeNode, found bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
n := tree.root
for n != nil {
c := tree.comparator(key, n.Key)
switch {
case c == 0:
return n, true
case c < 0:
n = n.children[0]
case c > 0:
floor, found = n, true
n = n.children[1]
}
}
if found {
return
}
return nil, false
}
// Ceiling finds ceiling node of the input key, return the ceiling node or nil if no ceiling node is found.
// Second return parameter is true if ceiling was found, otherwise false.
//
// Ceiling node is defined as the smallest node that is larger than or equal to the given node.
// A ceiling node may not be found, either because the tree is empty, or because
// all nodes in the tree is smaller than the given node.
//
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (tree *AVLTree) Ceiling(key interface{}) (ceiling *AVLTreeNode, found bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
n := tree.root
for n != nil {
c := tree.comparator(key, n.Key)
switch {
case c == 0:
return n, true
case c > 0:
n = n.children[1]
case c < 0:
ceiling, found = n, true
n = n.children[0]
}
}
if found {
return
}
return nil, false
}
// Clear removes all nodes from the tree.
func (tree *AVLTree) Clear() {
tree.mu.Lock()
defer tree.mu.Unlock()
tree.root = nil
tree.size = 0
}
// Replace the data of the tree with given <data>.
func (tree *AVLTree) Replace(data map[interface{}]interface{}) {
tree.mu.Lock()
defer tree.mu.Unlock()
tree.root = nil
tree.size = 0
for key, value := range data {
tree.put(key, value, nil, &tree.root)
}
}
// String returns a string representation of container
func (tree *AVLTree) String() string {
tree.mu.RLock()
defer tree.mu.RUnlock()
str := ""
if tree.size != 0 {
output(tree.root, "", true, &str)
}
return str
}
// Print prints the tree to stdout.
func (tree *AVLTree) Print() {
fmt.Println(tree.String())
}
// Map returns all key-value items as map.
func (tree *AVLTree) Map() map[interface{}]interface{} {
m := make(map[interface{}]interface{}, tree.Size())
tree.IteratorAsc(func(key, value interface{}) bool {
m[key] = value
return true
})
return m
}
// MapStrAny returns all key-value items as map[string]interface{}.
func (tree *AVLTree) MapStrAny() map[string]interface{} {
m := make(map[string]interface{}, tree.Size())
tree.IteratorAsc(func(key, value interface{}) bool {
m[gconv.String(key)] = value
return true
})
return m
}
// Flip exchanges key-value of the tree to value-key.
// Note that you should guarantee the value is the same type as key,
// or else the comparator would panic.
//
// If the type of value is different with key, you pass the new <comparator>.
func (tree *AVLTree) Flip(comparator ...func(v1, v2 interface{}) int) {
t := (*AVLTree)(nil)
if len(comparator) > 0 {
t = NewAVLTree(comparator[0], !tree.mu.IsSafe())
} else {
t = NewAVLTree(tree.comparator, !tree.mu.IsSafe())
}
tree.IteratorAsc(func(key, value interface{}) bool {
t.put(value, key, nil, &t.root)
return true
})
tree.mu.Lock()
tree.root = t.root
tree.size = t.size
tree.mu.Unlock()
}
// Iterator is alias of IteratorAsc.
func (tree *AVLTree) Iterator(f func(key, value interface{}) bool) {
tree.IteratorAsc(f)
}
// IteratorFrom is alias of IteratorAscFrom.
func (tree *AVLTree) IteratorFrom(key interface{}, match bool, f func(key, value interface{}) bool) {
tree.IteratorAscFrom(key, match, f)
}
// IteratorAsc iterates the tree in ascending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (tree *AVLTree) IteratorAsc(f func(key, value interface{}) bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
tree.doIteratorAsc(tree.bottom(0), f)
}
// IteratorAscFrom iterates the tree in ascending order with given callback function <f>.
// The parameter <key> specifies the start entry for iterating. The <match> specifies whether
// starting iterating if the <key> is fully matched, or else using index searching iterating.
// If <f> returns true, then it continues iterating; or false to stop.
func (tree *AVLTree) IteratorAscFrom(key interface{}, match bool, f func(key, value interface{}) bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
node, found := tree.doSearch(key)
if match {
if found {
tree.doIteratorAsc(node, f)
}
} else {
tree.doIteratorAsc(node, f)
}
}
func (tree *AVLTree) doIteratorAsc(node *AVLTreeNode, f func(key, value interface{}) bool) {
for node != nil {
if !f(node.Key, node.Value) {
return
}
node = node.Next()
}
}
// IteratorDesc iterates the tree in descending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (tree *AVLTree) IteratorDesc(f func(key, value interface{}) bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
tree.doIteratorDesc(tree.bottom(1), f)
}
// IteratorDescFrom iterates the tree in descending order with given callback function <f>.
// The parameter <key> specifies the start entry for iterating. The <match> specifies whether
// starting iterating if the <key> is fully matched, or else using index searching iterating.
// If <f> returns true, then it continues iterating; or false to stop.
func (tree *AVLTree) IteratorDescFrom(key interface{}, match bool, f func(key, value interface{}) bool) {
tree.mu.RLock()
defer tree.mu.RUnlock()
node, found := tree.doSearch(key)
if match {
if found {
tree.doIteratorDesc(node, f)
}
} else {
tree.doIteratorDesc(node, f)
}
}
func (tree *AVLTree) doIteratorDesc(node *AVLTreeNode, f func(key, value interface{}) bool) {
for node != nil {
if !f(node.Key, node.Value) {
return
}
node = node.Prev()
}
}
func (tree *AVLTree) put(key interface{}, value interface{}, p *AVLTreeNode, qp **AVLTreeNode) bool {
q := *qp
if q == nil {
tree.size++
*qp = &AVLTreeNode{Key: key, Value: value, parent: p}
return true
}
c := tree.comparator(key, q.Key)
if c == 0 {
q.Key = key
q.Value = value
return false
}
if c < 0 {
c = -1
} else {
c = 1
}
a := (c + 1) / 2
if tree.put(key, value, q, &q.children[a]) {
return putFix(int8(c), qp)
}
return false
}
func (tree *AVLTree) remove(key interface{}, qp **AVLTreeNode) (value interface{}, fix bool) {
q := *qp
if q == nil {
return nil, false
}
c := tree.comparator(key, q.Key)
if c == 0 {
tree.size--
value = q.Value
fix = true
if q.children[1] == nil {
if q.children[0] != nil {
q.children[0].parent = q.parent
}
*qp = q.children[0]
return
}
if removeMin(&q.children[1], &q.Key, &q.Value) {
return value, removeFix(-1, qp)
}
return
}
if c < 0 {
c = -1
} else {
c = 1
}
a := (c + 1) / 2
value, fix = tree.remove(key, &q.children[a])
if fix {
return value, removeFix(int8(-c), qp)
}
return value, false
}
func removeMin(qp **AVLTreeNode, minKey *interface{}, minVal *interface{}) bool {
q := *qp
if q.children[0] == nil {
*minKey = q.Key
*minVal = q.Value
if q.children[1] != nil {
q.children[1].parent = q.parent
}
*qp = q.children[1]
return true
}
fix := removeMin(&q.children[0], minKey, minVal)
if fix {
return removeFix(1, qp)
}
return false
}
func putFix(c int8, t **AVLTreeNode) bool {
s := *t
if s.b == 0 {
s.b = c
return true
}
if s.b == -c {
s.b = 0
return false
}
if s.children[(c+1)/2].b == c {
s = singleRotate(c, s)
} else {
s = doubleRotate(c, s)
}
*t = s
return false
}
func removeFix(c int8, t **AVLTreeNode) bool {
s := *t
if s.b == 0 {
s.b = c
return false
}
if s.b == -c {
s.b = 0
return true
}
a := (c + 1) / 2
if s.children[a].b == 0 {
s = rotate(c, s)
s.b = -c
*t = s
return false
}
if s.children[a].b == c {
s = singleRotate(c, s)
} else {
s = doubleRotate(c, s)
}
*t = s
return true
}
func singleRotate(c int8, s *AVLTreeNode) *AVLTreeNode {
s.b = 0
s = rotate(c, s)
s.b = 0
return s
}
func doubleRotate(c int8, s *AVLTreeNode) *AVLTreeNode {
a := (c + 1) / 2
r := s.children[a]
s.children[a] = rotate(-c, s.children[a])
p := rotate(c, s)
switch {
default:
s.b = 0
r.b = 0
case p.b == c:
s.b = -c
r.b = 0
case p.b == -c:
s.b = 0
r.b = c
}
p.b = 0
return p
}
func rotate(c int8, s *AVLTreeNode) *AVLTreeNode {
a := (c + 1) / 2
r := s.children[a]
s.children[a] = r.children[a^1]
if s.children[a] != nil {
s.children[a].parent = s
}
r.children[a^1] = s
r.parent = s.parent
s.parent = r
return r
}
func (tree *AVLTree) bottom(d int) *AVLTreeNode {
n := tree.root
if n == nil {
return nil
}
for c := n.children[d]; c != nil; c = n.children[d] {
n = c
}
return n
}
// Prev returns the previous element in an inorder
// walk of the AVL tree.
func (node *AVLTreeNode) Prev() *AVLTreeNode {
return node.walk1(0)
}
// Next returns the next element in an inorder
// walk of the AVL tree.
func (node *AVLTreeNode) Next() *AVLTreeNode {
return node.walk1(1)
}
func (node *AVLTreeNode) walk1(a int) *AVLTreeNode {
if node == nil {
return nil
}
n := node
if n.children[a] != nil {
n = n.children[a]
for n.children[a^1] != nil {
n = n.children[a^1]
}
return n
}
p := n.parent
for p != nil && p.children[a] == n {
n = p
p = p.parent
}
return p
}
func output(node *AVLTreeNode, 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 += fmt.Sprintf("%v\n", node.Key)
if node.children[0] != nil {
newPrefix := prefix
if isTail {
newPrefix += " "
} else {
newPrefix += "│ "
}
output(node.children[0], newPrefix, true, str)
}
}
// MarshalJSON implements the interface MarshalJSON for json.Marshal.
func (tree *AVLTree) MarshalJSON() ([]byte, error) {
return json.Marshal(tree.Map())
}