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Best algorithm for detecting cycles in a directed graph [closed]
What is the most efficient algorithm for detecting all cycles within a directed graph?
14 Answers
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How to override the [] operator in Python?
...rwise this will happen:
>>> myobj[5] = 1
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: MyClass instance has no attribute '__setitem__'
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C# 5 async CTP: why is internal “state” set to 0 in generated code before EndAwait call?
... code looked like, and the GetAwaiter() / BeginAwait() / EndAwait() calls.
4 Answers
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Iterate over model instance field names and values in template
...f that instance in table format, with the field name (verbose_name specifically if specified on the field) in the first column and the value of that field in the second column.
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Django select only rows with duplicate field values
... syntax is also how Django interprets you wanting to do a join. So, essentially when you try to filter on that, Django thinks you're trying to do a join with count which obviously doesn't exist. The fix is to specify a name for your annotation result, i.e. annotate(mycount=Count('id')) and then filt...
JavaScript: What are .extend and .prototype used for?
...ate ).lol() // alert message
In the snippet above, I define a method for all Date objects ( already existing ones and all new ones ).
extend is usually a high level function that copies the prototype of a new subclass that you want to extend from the base class.
So you can do something like:
e...
Where in a virtualenv does the custom code go?
... instance, if I were building a WSGI application and created a virtualenv called foobar I would start with a directory structure like:
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How to set child process' environment variable in Makefile
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I have GNU make 3.81, and all: <\n\t>export PROJ_ROOT=$(CURDIR)<\n\t>echo $(PROJ_ROOT)<\n> outputs the correct expansion for the first row, but only echo for the second one. PROJ_ROOT is not set after running make. Spaces around = gi...
What does pylint's “Too few public methods” message mean
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The error basically says that classes aren't meant to just store data, as you're basically treating the class as a dictionary. Classes should have at least a few methods to operate on the data that they hold.
If your class looks like this:...
Scala 2.8 breakOut
...breakOut itself. It is of type CanBuildFrom[Nothing,T,To]. We already know all these types, so we can determine that we need an implicit of type CanBuildFrom[Nothing,(Int,String),Map[Int,String]]. But is there such a definition?
Let's look at CanBuildFrom's definition:
trait CanBuildFrom[-From, -E...