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102 lines
2.5 KiB
Go
102 lines
2.5 KiB
Go
/*
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Copyright (c) Emir Pasic, All rights reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 3.0 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library. See the file LICENSE included
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with this distribution for more information.
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*/
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// Implementation of set backed by a hash table.
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// Structure is not thread safe.
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// References: http://en.wikipedia.org/wiki/Set_%28abstract_data_type%29
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package hashset
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import (
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"fmt"
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"strings"
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)
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type Set struct {
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items map[interface{}]struct{}
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}
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var itemExists = struct{}{}
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// Instantiates a new empty set
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func New() *Set {
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return &Set{items: make(map[interface{}]struct{})}
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}
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// Adds the items (one or more) to the set.
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func (set *Set) Add(items ...interface{}) {
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for _, item := range items {
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set.items[item] = itemExists
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}
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}
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// Removes the items (one or more) from the set.
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func (set *Set) Remove(items ...interface{}) {
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for _, item := range items {
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delete(set.items, item)
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}
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}
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// Check wether items (one or more) are present in the set.
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// All items have to be present in the set for the method to return true.
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// Returns true if no arguments are passed at all, i.e. set is always superset of empty set.
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func (set *Set) Contains(items ...interface{}) bool {
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for _, item := range items {
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if _, contains := set.items[item]; !contains {
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return false
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}
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}
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return true
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}
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// Returns true if set does not contain any elements.
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func (set *Set) Empty() bool {
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return set.Size() == 0
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}
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// Returns number of elements within the set.
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func (set *Set) Size() int {
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return len(set.items)
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}
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// Clears all values in the set.
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func (set *Set) Clear() {
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set.items = make(map[interface{}]struct{})
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}
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// Returns all items in the set.
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func (set *Set) Values() []interface{} {
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values := make([]interface{}, set.Size())
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count := 0
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for item, _ := range set.items {
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values[count] = item
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count += 1
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}
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return values
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}
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func (set *Set) String() string {
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str := "HashSet\n"
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items := []string{}
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for k, _ := range set.items {
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items = append(items, fmt.Sprintf("%v", k))
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}
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str += strings.Join(items, ", ")
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return str
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}
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