60 lines
1.7 KiB
Rust
60 lines
1.7 KiB
Rust
use petgraph::{algo::min_spanning_tree, dot::Dot, graph::UnGraph, Graph};
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#[test]
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fn mst() {
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use petgraph::data::FromElements;
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let mut gr = Graph::<_, _>::new();
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let a = gr.add_node("A");
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let b = gr.add_node("B");
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let c = gr.add_node("C");
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let d = gr.add_node("D");
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let e = gr.add_node("E");
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let f = gr.add_node("F");
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let g = gr.add_node("G");
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gr.add_edge(a, b, 7.);
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gr.add_edge(a, d, 5.);
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gr.add_edge(d, b, 9.);
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gr.add_edge(b, c, 8.);
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gr.add_edge(b, e, 7.);
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gr.add_edge(c, e, 5.);
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gr.add_edge(d, e, 15.);
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gr.add_edge(d, f, 6.);
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gr.add_edge(f, e, 8.);
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gr.add_edge(f, g, 11.);
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gr.add_edge(e, g, 9.);
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// add a disjoint part
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let h = gr.add_node("H");
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let i = gr.add_node("I");
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let j = gr.add_node("J");
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gr.add_edge(h, i, 1.);
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gr.add_edge(h, j, 3.);
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gr.add_edge(i, j, 1.);
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println!("{}", Dot::new(&gr));
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let mst = UnGraph::from_elements(min_spanning_tree(&gr));
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println!("{}", Dot::new(&mst));
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println!("{:?}", Dot::new(&mst));
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println!("MST is:\n{:#?}", mst);
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assert!(mst.node_count() == gr.node_count());
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// |E| = |N| - 2 because there are two disconnected components.
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assert!(mst.edge_count() == gr.node_count() - 2);
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// check the exact edges are there
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assert!(mst.find_edge(a, b).is_some());
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assert!(mst.find_edge(a, d).is_some());
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assert!(mst.find_edge(b, e).is_some());
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assert!(mst.find_edge(e, c).is_some());
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assert!(mst.find_edge(e, g).is_some());
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assert!(mst.find_edge(d, f).is_some());
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assert!(mst.find_edge(h, i).is_some());
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assert!(mst.find_edge(i, j).is_some());
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assert!(mst.find_edge(d, b).is_none());
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assert!(mst.find_edge(b, c).is_none());
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}
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