34 lines
844 B
Dart
34 lines
844 B
Dart
import 'package:dartterm/algorithms/union_find.dart';
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class Edge<T> {
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final int src, dst;
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final T value;
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final double score; // higher score is better
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const Edge(this.src, this.dst, this.value, this.score);
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}
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List<Edge<T>> kruskal<T>(int nRegions, List<Edge<T>> srcEdges) {
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var edges = List.from(srcEdges); // copy so we can mutate it
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edges.sort((e0, e1) => -e0.score.compareTo(e1.score));
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List<Edge<T>> spanningEdges = [];
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var connected = UnionFind(nRegions);
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for (var i = 0; i < edges.length; i++) {
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var edge = edges[i];
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if (connected.find(edge.src) == connected.find(edge.dst)) {
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continue;
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}
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spanningEdges.add(edge);
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connected.union(edge.src, edge.dst);
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// break early if we run out of regions
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nRegions -= 1;
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if (nRegions == 1) {
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break;
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}
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}
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return spanningEdges;
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}
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