forked from LaconicNetwork/kompose
59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
// Copyright ©2014 The gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package topo
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import (
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"github.com/gonum/graph"
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"github.com/gonum/graph/traverse"
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)
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// IsPathIn returns whether path is a path in g.
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//
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// As special cases, IsPathIn returns true for a zero length path or for
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// a path of length 1 when the node in path exists in the graph.
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func IsPathIn(g graph.Graph, path []graph.Node) bool {
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switch len(path) {
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case 0:
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return true
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case 1:
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return g.Has(path[0])
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default:
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var canReach func(u, v graph.Node) bool
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switch g := g.(type) {
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case graph.Directed:
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canReach = g.HasEdgeFromTo
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default:
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canReach = g.HasEdge
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}
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for i, u := range path[:len(path)-1] {
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if !canReach(u, path[i+1]) {
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return false
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}
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}
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return true
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}
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}
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// ConnectedComponents returns the connected components of the undirected graph g.
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func ConnectedComponents(g graph.Undirected) [][]graph.Node {
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var (
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w traverse.DepthFirst
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c []graph.Node
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cc [][]graph.Node
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)
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during := func(n graph.Node) {
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c = append(c, n)
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}
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after := func() {
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cc = append(cc, []graph.Node(nil))
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cc[len(cc)-1] = append(cc[len(cc)-1], c...)
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c = c[:0]
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}
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w.WalkAll(g, nil, after, during)
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return cc
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}
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