Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings

Commit 6f414cd

Browse files
committed
Extract BronKerbosch to library
1 parent fe45dcf commit 6f414cd

File tree

3 files changed

+36
-56
lines changed

3 files changed

+36
-56
lines changed

‎src/main/scala/eu/sim642/adventofcode2018/Day23.scala

Lines changed: 2 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ import eu.sim642.adventofcodelib.box.{Box3, Box4}
44
import eu.sim642.adventofcodelib.pos.Pos3
55
import eu.sim642.adventofcodelib.pos.Pos4
66
import eu.sim642.adventofcodelib.IntegralImplicits.*
7+
import eu.sim642.adventofcodelib.graph.BronKerbosch
78

89
import scala.collection.mutable
910
import scala.util.boundary
@@ -40,35 +41,9 @@ object Day23 {
4041
}
4142

4243
object NaiveCliquePart2Solution extends Part2Solution {
43-
def maximumClique(neighbors: Map[Nanobot, Set[Nanobot]]): Set[Nanobot] = {
44-
var best: Set[Nanobot] = Set.empty
45-
46-
def bronKerbosh(r: Set[Nanobot], p: Set[Nanobot], x: Set[Nanobot]): Unit = {
47-
if (p.isEmpty && x.isEmpty) {
48-
//println(r)
49-
if (r.size > best.size)
50-
best = r
51-
}
52-
else {
53-
//val u = p.headOption.getOrElse(x.head)
54-
val u = (p ++ x).maxBy(neighbors(_).size) // pivot on highest degree
55-
var p2 = p
56-
var x2 = x
57-
for (v <- p -- neighbors(u)) {
58-
bronKerbosh(r + v, p2 intersect neighbors(v), x2 intersect neighbors(v))
59-
p2 -= v
60-
x2 += v
61-
}
62-
}
63-
}
64-
65-
bronKerbosh(Set.empty, neighbors.keySet, Set.empty)
66-
best
67-
}
68-
6944
def maximumOverlap(nanobots: Seq[Nanobot]): Set[Nanobot] = {
7045
val neighbors: Map[Nanobot, Set[Nanobot]] = nanobots.map(nanobot1 => nanobot1 -> nanobots.filter(nanobot2 => nanobot2 != nanobot1 && nanobot1.overlaps(nanobot2)).toSet).toMap
71-
maximumClique(neighbors)
46+
BronKerbosch.maximumClique(neighbors)
7247
}
7348

7449
def closestMostNanobots(nanobots: Seq[Nanobot]): Int = {

‎src/main/scala/eu/sim642/adventofcode2024/Day23.scala

Lines changed: 3 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,7 @@
11
package eu.sim642.adventofcode2024
22

3+
import eu.sim642.adventofcodelib.graph.BronKerbosch
4+
35
object Day23 {
46

57
type Computer = String
@@ -16,37 +18,9 @@ object Day23 {
1618

1719
def count3CliquesT(edges: Set[Edge]): Int = find3Cliques(edges).count(_.exists(_.startsWith("t")))
1820

19-
// copied from 2018 day 23
20-
// TODO: move to library
21-
def maximumClique(neighbors: Map[Computer, Set[Computer]]): Set[Computer] = {
22-
var best: Set[Computer] = Set.empty
23-
24-
def bronKerbosh(r: Set[Computer], p: Set[Computer], x: Set[Computer]): Unit = {
25-
if (p.isEmpty && x.isEmpty) {
26-
//println(r)
27-
if (r.size > best.size)
28-
best = r
29-
}
30-
else {
31-
//val u = p.headOption.getOrElse(x.head)
32-
val u = (p ++ x).maxBy(neighbors(_).size) // pivot on highest degree
33-
var p2 = p
34-
var x2 = x
35-
for (v <- p -- neighbors(u)) {
36-
bronKerbosh(r + v, p2 intersect neighbors(v), x2 intersect neighbors(v))
37-
p2 -= v
38-
x2 += v
39-
}
40-
}
41-
}
42-
43-
bronKerbosh(Set.empty, neighbors.keySet, Set.empty)
44-
best
45-
}
46-
4721
def maximumClique(edges: Set[Edge]): Set[Computer] = {
4822
val neighbors = (edges ++ edges.map(_.swap)).groupMap(_._1)(_._2)
49-
maximumClique(neighbors)
23+
BronKerbosch.maximumClique(neighbors)
5024
}
5125

5226
def lanPartyPassword(edges: Set[Edge]): String = {
Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,31 @@
1+
package eu.sim642.adventofcodelib.graph
2+
3+
object BronKerbosch {
4+
5+
// moved from 2018 day 23
6+
def maximumClique[A](neighbors: Map[A, Set[A]]): Set[A] = {
7+
var best: Set[A] = Set.empty
8+
9+
def bronKerbosch(r: Set[A], p: Set[A], x: Set[A]): Unit = {
10+
if (p.isEmpty && x.isEmpty) {
11+
//println(r)
12+
if (r.size > best.size)
13+
best = r
14+
}
15+
else {
16+
//val u = p.headOption.getOrElse(x.head)
17+
val u = (p ++ x).maxBy(neighbors(_).size) // pivot on highest degree
18+
var p2 = p
19+
var x2 = x
20+
for (v <- p -- neighbors(u)) {
21+
bronKerbosch(r + v, p2 intersect neighbors(v), x2 intersect neighbors(v))
22+
p2 -= v
23+
x2 += v
24+
}
25+
}
26+
}
27+
28+
bronKerbosch(Set.empty, neighbors.keySet, Set.empty)
29+
best
30+
}
31+
}

0 commit comments

Comments
(0)

AltStyle によって変換されたページ (->オリジナル) /