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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package containers
type intervalKey[K Ordered[K]] struct {
Min, Max K
}
func (ival intervalKey[K]) ContainsFn(fn func(K) int) bool {
return fn(ival.Min) >= 0 && fn(ival.Max) <= 0
}
func (a intervalKey[K]) Cmp(b intervalKey[K]) int {
if d := a.Min.Cmp(b.Min); d != 0 {
return d
}
return a.Max.Cmp(b.Max)
}
type intervalValue[K Ordered[K], V any] struct {
Val V
SpanOfChildren intervalKey[K]
}
type IntervalTree[K Ordered[K], V any] struct {
MinFn func(V) K
MaxFn func(V) K
inner RBTree[intervalKey[K], intervalValue[K, V]]
}
func (t *IntervalTree[K, V]) keyFn(v intervalValue[K, V]) intervalKey[K] {
return intervalKey[K]{
Min: t.MinFn(v.Val),
Max: t.MaxFn(v.Val),
}
}
func (t *IntervalTree[K, V]) attrFn(node *RBNode[intervalValue[K, V]]) {
max := t.MaxFn(node.Value.Val)
if node.Left != nil && node.Left.Value.SpanOfChildren.Max.Cmp(max) > 0 {
max = node.Left.Value.SpanOfChildren.Max
}
if node.Right != nil && node.Right.Value.SpanOfChildren.Max.Cmp(max) > 0 {
max = node.Right.Value.SpanOfChildren.Max
}
node.Value.SpanOfChildren.Max = max
min := t.MinFn(node.Value.Val)
if node.Left != nil && node.Left.Value.SpanOfChildren.Min.Cmp(min) < 0 {
min = node.Left.Value.SpanOfChildren.Min
}
if node.Right != nil && node.Right.Value.SpanOfChildren.Min.Cmp(min) < 0 {
min = node.Right.Value.SpanOfChildren.Min
}
node.Value.SpanOfChildren.Min = min
}
func (t *IntervalTree[K, V]) init() {
if t.inner.KeyFn == nil {
t.inner.KeyFn = t.keyFn
t.inner.AttrFn = t.attrFn
}
}
func (t *IntervalTree[K, V]) Delete(min, max K) {
t.init()
t.inner.Delete(intervalKey[K]{
Min: min,
Max: max,
})
}
func (t *IntervalTree[K, V]) Equal(u *IntervalTree[K, V]) bool {
return t.inner.Equal(&u.inner)
}
func (t *IntervalTree[K, V]) Insert(val V) {
t.init()
t.inner.Insert(intervalValue[K, V]{Val: val})
}
func (t *IntervalTree[K, V]) Min() (K, bool) {
if t.inner.root == nil {
var zero K
return zero, false
}
return t.inner.root.Value.SpanOfChildren.Min, true
}
func (t *IntervalTree[K, V]) Max() (K, bool) {
if t.inner.root == nil {
var zero K
return zero, false
}
return t.inner.root.Value.SpanOfChildren.Max, true
}
func (t *IntervalTree[K, V]) Lookup(k K) (V, bool) {
return t.Search(k.Cmp)
}
func (t *IntervalTree[K, V]) Search(fn func(K) int) (V, bool) {
node := t.inner.root
for node != nil {
switch {
case t.keyFn(node.Value).ContainsFn(fn):
return node.Value.Val, true
case node.Left != nil && node.Left.Value.SpanOfChildren.ContainsFn(fn):
node = node.Left
case node.Right != nil && node.Right.Value.SpanOfChildren.ContainsFn(fn):
node = node.Right
default:
node = nil
}
}
var zero V
return zero, false
}
func (t *IntervalTree[K, V]) searchAll(fn func(K) int, node *RBNode[intervalValue[K, V]], ret *[]V) {
if node == nil {
return
}
if !node.Value.SpanOfChildren.ContainsFn(fn) {
return
}
t.searchAll(fn, node.Left, ret)
if t.keyFn(node.Value).ContainsFn(fn) {
*ret = append(*ret, node.Value.Val)
}
t.searchAll(fn, node.Right, ret)
}
func (t *IntervalTree[K, V]) SearchAll(fn func(K) int) []V {
var ret []V
t.searchAll(fn, t.inner.root, &ret)
return ret
}
// TODO: func (t *IntervalTree[K, V]) Walk(fn func(*RBNode[V]) error) error
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