117 lines
2.2 KiB
Go
117 lines
2.2 KiB
Go
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// Copyright (c) 2016 Bitfury Group Limited
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// Distributed under the MIT software license, see the accompanying
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// file LICENSE or http://www.opensource.org/licenses/mit-license.php
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package prefix_tree
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import "errors"
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// Node represents the general interface for node in prefix tree
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type Node interface {
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Name() string
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Len() int
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Child(nextSymbol string) Node
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Childs() map[string]Node
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AddChild(symbol string, child Node) error
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Parent() Node
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PreviousSymbol() string
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IsRoot() bool
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IsLeaf() bool
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IsTerminal() bool
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Terminal()
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Path() (string, error)
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}
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type node struct {
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name string
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childs map[string]Node
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parent Node
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previousSymbol string
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isTerminal bool
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}
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// NewNode create new node
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func NewNode(name string, parent Node, previousSymbol string, isTerminal bool) Node {
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return &node{
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name: name,
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childs: make(map[string]Node),
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parent: parent,
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previousSymbol: previousSymbol,
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isTerminal: isTerminal,
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}
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}
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func (nd *node) Name() string {
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return nd.name
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}
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func (nd *node) Len() int {
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return len(nd.childs)
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}
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func (nd *node) Child(nextSymbol string) Node {
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if _, ok := nd.childs[nextSymbol]; !ok {
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return nil
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}
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return nd.childs[nextSymbol]
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}
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func (nd *node) Childs() map[string]Node {
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return nd.childs
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}
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func (nd *node) AddChild(symbol string, child Node) error {
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if _, ok := nd.childs[symbol]; ok {
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return errors.New("Node already exists")
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}
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nd.childs[symbol] = child
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return nil
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}
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func (nd *node) Parent() Node {
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return nd.parent
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}
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func (nd *node) PreviousSymbol() string {
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return nd.previousSymbol
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}
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func (nd *node) IsRoot() bool {
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return nd.parent == nil
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}
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func (nd *node) IsLeaf() bool {
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return len(nd.childs) == 0
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}
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func (nd *node) IsTerminal() bool {
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return nd.isTerminal
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}
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func (nd *node) Terminal() {
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nd.isTerminal = true
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}
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func (nd *node) Path() (path string, err error) {
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var xNode Node = nd
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for {
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if xNode.IsRoot() {
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break
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}
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path += xNode.PreviousSymbol()
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if xNode == xNode.Parent() {
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return "", CyclicDataError
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}
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xNode = xNode.Parent()
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}
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return Reverse(path), nil
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}
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func Reverse(reversePath string) (path string) {
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length := len(reversePath)
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for i := length - 1; i >= 0; i-- {
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path += string(reversePath[i])
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}
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return path
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}
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