61 lines
1.7 KiB
Python
61 lines
1.7 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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# IMPORTS
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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from __future__ import annotations;
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from src.thirdparty.types import *;
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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# EXPORTS
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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__all__ = [
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'Graph',
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];
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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# CLASS Graph
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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class Graph(object):
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'''
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a data structure for graphs
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'''
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nodes: list[Any];
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edges: list[tuple[Any,Any]]
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def __init__(self, nodes: list[Any], edges: list[tuple[Any,Any]]):
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self.nodes = nodes;
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self.edges = edges;
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return;
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def __len__(self) -> int:
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return len(self.nodes);
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def subgraph(self, nodes: list[Any]) -> Graph:
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'''
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@returns graph induced by subset of nodes
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'''
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return Graph(
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nodes = [ u for u in self.nodes if u in nodes ],
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edges = [ (u, v) for u, v in self.edges if u in nodes and v in nodes ],
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);
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def successors(self, u: str):
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'''
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@returns
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list of successor nodes
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'''
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return [ v for (u_, v) in self.edges if u == u_ ];
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def predecessors(self, v: str):
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'''
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@returns
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list of predecessor nodes
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'''
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return [ u for (u, v_) in self.edges if v == v_ ];
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