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// Copyright (c) 2015, Emir Pasic. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package treemap implements a map backed by red-black tree.
//
// Elements are ordered by key in the map.
//
// Structure is not thread safe.
//
// Reference: http://en.wikipedia.org/wiki/Associative_array
package treemap
import (
"fmt"
"github.com/emirpasic/gods/maps"
rbt "github.com/emirpasic/gods/trees/redblacktree"
"github.com/emirpasic/gods/utils"
"strings"
)
func assertMapImplementation() {
var _ maps.Map = (*Map)(nil)
}
// Map holds the elements in a red-black tree
type Map struct {
tree *rbt.Tree
}
// NewWith instantiates a tree map with the custom comparator.
func NewWith(comparator utils.Comparator) *Map {
return &Map{tree: rbt.NewWith(comparator)}
}
// NewWithIntComparator instantiates a tree map with the IntComparator, i.e. keys are of type int.
func NewWithIntComparator() *Map {
return &Map{tree: rbt.NewWithIntComparator()}
}
// NewWithStringComparator instantiates a tree map with the StringComparator, i.e. keys are of type string.
func NewWithStringComparator() *Map {
return &Map{tree: rbt.NewWithStringComparator()}
}
// Put inserts key-value pair into the map.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Put(key interface{}, value interface{}) {
m.tree.Put(key, value)
}
// Get searches the element in the map by key and returns its value or nil if key is not found in tree.
// Second return parameter is true if key was found, otherwise false.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Get(key interface{}) (value interface{}, found bool) {
return m.tree.Get(key)
}
// Remove removes the element from the map by key.
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Remove(key interface{}) {
m.tree.Remove(key)
}
// Empty returns true if map does not contain any elements
func (m *Map) Empty() bool {
return m.tree.Empty()
}
// Size returns number of elements in the map.
func (m *Map) Size() int {
return m.tree.Size()
}
// Keys returns all keys in-order
func (m *Map) Keys() []interface{} {
return m.tree.Keys()
}
// Values returns all values in-order based on the key.
func (m *Map) Values() []interface{} {
return m.tree.Values()
}
// Clear removes all elements from the map.
func (m *Map) Clear() {
m.tree.Clear()
}
// Min returns the minimum key and its value from the tree map.
// Returns nil, nil if map is empty.
func (m *Map) Min() (key interface{}, value interface{}) {
if node := m.tree.Left(); node != nil {
return node.Key, node.Value
}
return nil, nil
}
// Max returns the maximum key and its value from the tree map.
// Returns nil, nil if map is empty.
func (m *Map) Max() (key interface{}, value interface{}) {
if node := m.tree.Right(); node != nil {
return node.Key, node.Value
}
return nil, nil
}
// Floor finds the floor key-value pair for the input key.
// In case that no floor is found, then both returned values will be nil.
// It's generally enough to check the first value (key) for nil, which determines if floor was found.
//
// Floor key is defined as the largest key that is smaller than or equal to the given key.
// A floor key may not be found, either because the map is empty, or because
// all keys in the map are larger than the given key.
//
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Floor(key interface{}) (foundKey interface{}, foundValue interface{}) {
node, found := m.tree.Floor(key)
if found {
return node.Key, node.Value
}
return nil, nil
}
// Ceiling finds the ceiling key-value pair for the input key.
// In case that no ceiling is found, then both returned values will be nil.
// It's generally enough to check the first value (key) for nil, which determines if ceiling was found.
//
// Ceiling key is defined as the smallest key that is larger than or equal to the given key.
// A ceiling key may not be found, either because the map is empty, or because
// all keys in the map are smaller than the given key.
//
// Key should adhere to the comparator's type assertion, otherwise method panics.
func (m *Map) Ceiling(key interface{}) (foundKey interface{}, foundValue interface{}) {
node, found := m.tree.Ceiling(key)
if found {
return node.Key, node.Value
}
return nil, nil
}
// String returns a string representation of container
func (m *Map) String() string {
str := "TreeMap\nmap["
it := m.Iterator()
for it.Next() {
str += fmt.Sprintf("%v:%v ", it.Key(), it.Value())
}
return strings.TrimRight(str, " ") + "]"
}
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