大约有 31,500 项符合查询结果（耗时：0.0386秒） [XML]
What is pseudopolynomial time? How does it differ from polynomial time?
...ng TSP takes time O(n · n!), which isn't polynomial time.
These runtimes all refer to some variable n that tracks the size of the input. For example, in selection sort, n refers to the number of elements in the array, while in TSP n refers to the number of nodes in the graph. In order to standardi...
MySQL SELECT WHERE datetime matches day (and not necessarily time)
I have a table which contains a datetime column. I wish to return all records of a given day regardless of the time. Or in other words, if my table only contained the following 4 records, then only the 2nd and 3rd would be returned if I limit to 2012-12-25.
...
Is there a recommended format for multi-line imports?
...
Personally I go with parentheses when importing more than one component and sort them alphabetically. Like so:
from Tkinter import (
Button,
Canvas,
DISABLED,
END,
Entry,
Frame,
LEFT,
NORMAL,
RI...
AttributeError: 'module' object has no attribute
...ave mutual top-level imports, which is almost always a bad idea.
If you really must have mutual imports in Python, the way to do it is to import them within a function:
# In b.py:
def cause_a_to_do_something():
import a
a.do_something()
Now a.py can safely do import b without causing pro...
Remove Trailing Spaces and Update in Columns in SQL Server
I have trailing spaces in a column in a SQL Server table called Company Name .
13 Answers
...
Command line to remove an environment variable from the OS level configuration
...OBAR
If the variable is set in the system environment (e.g. if you originally set it with setx /M), as an administrator run:
REG delete "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /F /V FOOBAR
Note: The REG commands above won't affect any existing processes (and some new...
How to see which plugins are making Vim slow?
...:profile file *
" At this point do slow actions
:profile pause
:noautocmd qall!
(unlike quitting noautocmd is not really required, it just makes vim quit faster).
Note: you won’t get information about functions there were deleted before vim quit.
...
Are there any standard exit status codes in Linux?
...ld died with 11" */
}
How are you determining the exit status? Traditionally, the shell only stores an 8-bit return code, but sets the high bit if the process was abnormally terminated.
$ sh -c 'exit 42'; echo $?
42
$ sh -c 'kill -SEGV $$'; echo $?
Segmentation fault
139
$ expr 139 - 128
11
I...
Mocking member variables of a class using Mockito
...ing to make. Factor the sequence diagram into the objects that you can actually control. This means that if you are working with a framework class which has the dependent object anti-pattern you show above, then you should regard the object and its badly-factored member as a single unit in terms of ...
What to add for the update portion in ConcurrentDictionary AddOrUpdate
...d] = sessionId;
Store a key/value pair into the dictionary unconditionally, overwriting any value for that key if the key already exists: Use the indexer’s setter
(See: http://blogs.msdn.com/b/pfxteam/archive/2010/01/08/9945809.aspx)
The indexer is atomic, too. If you pass a function inst...