59 lines
1.4 KiB
Python
59 lines
1.4 KiB
Python
from topo_sort import topo_sort
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def check(order, edges):
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pos = {n:i for i,n in enumerate(order)}
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for u,v in edges:
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assert pos[u] < pos[v], (u,v,order)
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# DAG basic
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order, cyc = topo_sort([1,2,3], [(1,2),(2,3)])
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assert cyc is None and order == [1,2,3], (order,cyc)
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check(order, [(1,2),(2,3)])
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# disconnected
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order, cyc = topo_sort([1,2,3,4], [(1,2)])
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assert cyc is None and set(order)=={1,2,3,4}
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check(order, [(1,2)])
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# deterministic tie-break
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order, cyc = topo_sort(["b","a","c"], [])
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assert order == ["a","b","c"], order
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# duplicate edges deduped
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order, cyc = topo_sort([1,2], [(1,2),(1,2)])
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assert cyc is None and order==[1,2]
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# cycle
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order, cyc = topo_sort([1,2,3], [(1,2),(2,3),(3,1)])
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assert cyc is not None
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# verify it's a cycle
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s = set(cyc)
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assert len(cyc) == len(s)+1 or len(cyc)==len(s), cyc # cycle list may include repeat? ours no repeat of first? we built v..u no repeat
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# check edges close
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edgeset = {(1,2),(2,3),(3,1)}
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# cycle consecutive
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for i in range(len(cyc)):
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a=cyc[i]; b=cyc[(i+1)%len(cyc)]
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assert (a,b) in edgeset, (a,b)
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print("cycle:", cyc)
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# self loop
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order, cyc = topo_sort([1], [(1,1)])
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assert cyc == [1], cyc
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# unknown node raises
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try:
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topo_sort([1], [(1,2)])
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raise SystemExit("expected ValueError")
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except ValueError:
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pass
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# duplicate node raises
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try:
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topo_sort([1,1], [])
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raise SystemExit("expected ValueError")
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except ValueError:
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pass
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print("ALL TESTS PASSED")
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