80 lines
1.8 KiB
Go
80 lines
1.8 KiB
Go
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package util
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// A simple trie implementation with Add an HasPrefix methods only.
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type Trie struct {
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children map[byte]*Trie
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wordTail bool
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word string
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}
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// CreateTrie creates a Trie and add all strings in the provided list to it.
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func CreateTrie(list []string) Trie {
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ret := Trie{
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children: make(map[byte]*Trie),
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wordTail: false,
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}
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for _, v := range list {
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ret.Add(v)
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}
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return ret
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}
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// Add adds a word to this trie
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func (t *Trie) Add(v string) {
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root := t
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for _, b := range []byte(v) {
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child, exists := root.children[b]
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if !exists {
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child = &Trie{
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children: make(map[byte]*Trie),
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wordTail: false,
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}
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root.children[b] = child
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}
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root = child
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}
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root.wordTail = true
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root.word = v
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}
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// HasPrefix returns true of v has any of the prefixes stored in this trie.
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func (t *Trie) HasPrefix(v string) bool {
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_, has := t.GetPrefix(v)
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return has
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}
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// GetPrefix is like HasPrefix but return the prefix in case of match or empty string otherwise.
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func (t *Trie) GetPrefix(v string) (string, bool) {
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root := t
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if root.wordTail {
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return root.word, true
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}
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for _, b := range []byte(v) {
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child, exists := root.children[b]
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if !exists {
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return "", false
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}
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if child.wordTail {
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return child.word, true
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}
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root = child
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}
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return "", false
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}
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