chen0040 /
pyalgs
| @@ 41-78 (lines=38) @@ | ||
| 38 | return self._id[v] |
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| 39 | ||
| 40 | ||
| 41 | class StronglyConnectedComponents(object): |
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| 42 | marked = None |
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| 43 | _id = None |
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| 44 | _count = 0 |
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| 45 | ||
| 46 | def __init__(self, G): |
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| 47 | if isinstance(G, EdgeWeightedGraph): |
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| 48 | raise ValueError('Graph must be directed graph for strongly connected components') |
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| 49 | if not isinstance(G, Digraph): |
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| 50 | raise ValueError('Graph must be directed graph for strongly connected components') |
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| 51 | ||
| 52 | vertex_count = G.vertex_count() |
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| 53 | self.marked = [False] * vertex_count |
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| 54 | self._id = [-1] * vertex_count |
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| 55 | ||
| 56 | dfo = DepthFirstOrder(G.reverse()) |
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| 57 | orders = dfo.postOrder() |
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| 58 | ||
| 59 | for v in orders: |
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| 60 | if not self.marked[v]: |
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| 61 | self.dfs(G, v) |
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| 62 | self._count += 1 |
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| 63 | ||
| 64 | def dfs(self, G, v): |
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| 65 | self.marked[v] = True |
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| 66 | self._id[v] = self._count |
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| 67 | for w in G.adj(v): |
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| 68 | if not self.marked[w]: |
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| 69 | self.dfs(G, w) |
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| 70 | ||
| 71 | def connected(self, v, w): |
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| 72 | return self._id[v] == self._id[w] |
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| 73 | ||
| 74 | def count(self): |
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| 75 | return self._count |
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| 76 | ||
| 77 | def id(self, v): |
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| 78 | return self._id[v] |
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| 79 | ||
| @@ 7-38 (lines=32) @@ | ||
| 4 | from pyalgs.data_structures.graphs.graph import EdgeWeightedGraph, Digraph |
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| 5 | ||
| 6 | ||
| 7 | class ConnectedComponents(object): |
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| 8 | marked = None |
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| 9 | _id = None |
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| 10 | _count = 0 |
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| 11 | ||
| 12 | def __init__(self, G): |
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| 13 | if isinstance(G, EdgeWeightedGraph): |
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| 14 | G = G.to_graph() |
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| 15 | ||
| 16 | vertex_count = G.vertex_count() |
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| 17 | self.marked = [False] * vertex_count |
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| 18 | self._id = [-1] * vertex_count |
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| 19 | for v in range(vertex_count): |
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| 20 | if not self.marked[v]: |
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| 21 | self.dfs(G, v) |
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| 22 | self._count += 1 |
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| 23 | ||
| 24 | def dfs(self, G, v): |
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| 25 | self.marked[v] = True |
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| 26 | self._id[v] = self._count |
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| 27 | for w in G.adj(v): |
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| 28 | if not self.marked[w]: |
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| 29 | self.dfs(G, w) |
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| 30 | ||
| 31 | def connected(self, v, w): |
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| 32 | return self._id[v] == self._id[w] |
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| 33 | ||
| 34 | def count(self): |
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| 35 | return self._count |
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| 36 | ||
| 37 | def id(self, v): |
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| 38 | return self._id[v] |
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| 39 | ||
| 40 | ||
| 41 | class StronglyConnectedComponents(object): |
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