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treeset.go
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treeset.go
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/*
Copyright (c) Emir Pasic, All rights reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library. See the file LICENSE included
with this distribution for more information.
*/
// Implementation of an ordered set backed by a red-black tree.
// Structure is not thread safe.
// References: http://en.wikipedia.org/wiki/Set_%28abstract_data_type%29
package treeset
import (
"fmt"
"github.com/emirpasic/gods/sets"
rbt "github.com/emirpasic/gods/trees/redblacktree"
"github.com/emirpasic/gods/utils"
"strings"
)
func assertInterfaceImplementation() {
var _ sets.Interface = (*Set)(nil)
}
type Set struct {
tree *rbt.Tree
}
var itemExists = struct{}{}
// Instantiates a new empty set with the custom comparator.
func NewWith(comparator utils.Comparator) *Set {
return &Set{tree: rbt.NewWith(comparator)}
}
// Instantiates a new empty set with the IntComparator, i.e. keys are of type int.
func NewWithIntComparator() *Set {
return &Set{tree: rbt.NewWithIntComparator()}
}
// Instantiates a new empty set with the StringComparator, i.e. keys are of type string.
func NewWithStringComparator() *Set {
return &Set{tree: rbt.NewWithStringComparator()}
}
// Adds the items (one or more) to the set.
func (set *Set) Add(items ...interface{}) {
for _, item := range items {
set.tree.Put(item, itemExists)
}
}
// Removes the items (one or more) from the set.
func (set *Set) Remove(items ...interface{}) {
for _, item := range items {
set.tree.Remove(item)
}
}
// Check wether items (one or more) are present in the set.
// All items have to be present in the set for the method to return true.
// Returns true if no arguments are passed at all, i.e. set is always superset of empty set.
func (set *Set) Contains(items ...interface{}) bool {
for _, item := range items {
if _, contains := set.tree.Get(item); !contains {
return false
}
}
return true
}
// Returns true if set does not contain any elements.
func (set *Set) Empty() bool {
return set.tree.Size() == 0
}
// Returns number of elements within the set.
func (set *Set) Size() int {
return set.tree.Size()
}
// Clears all values in the set.
func (set *Set) Clear() {
set.tree.Clear()
}
// Returns all items in the set.
func (set *Set) Values() []interface{} {
return set.tree.Keys()
}
func (set *Set) String() string {
str := "TreeSet\n"
items := []string{}
for _, v := range set.tree.Keys() {
items = append(items, fmt.Sprintf("%v", v))
}
str += strings.Join(items, ", ")
return str
}