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Why does Dijkstra's algorithm use decrease-key?
...ends on what priority queue you use. Here's a quick table that shows off different priority queues and the overall runtimes of the different Dijkstra's algorithm implementations:
Queue | T_e | T_d | T_k | w/o Dec-Key | w/Dec-Key
---------------+--------+--------+--------+------...
When and why would you seal a class?
...e it really made full sense, because it becomes expensive performance-wise if left untreated. The sealed keyword tells the CLR that there is no class further down to look for methods, and that speeds things up.
In most performance-enhancing tools on the market nowadays, you will find a checkbox th...
Change type of varchar field to integer: “cannot be cast automatically to type integer”
...ting integer or assign a varchar field to an integer one), so you must specify an explicit cast using ALTER TABLE ... ALTER COLUMN ... TYPE ... USING:
ALTER TABLE the_table ALTER COLUMN col_name TYPE integer USING (col_name::integer);
Note that you may have whitespace in your text fields; in that...
onSaveInstanceState () and onRestoreInstanceState ()
...restore the values in onCreate():
public void onCreate(Bundle icicle) {
if (icicle != null){
value = icicle.getLong("param");
}
}
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Return Boolean Value on SQL Select Statement
...
What you have there will return no row at all if the user doesn't exist. Here's what you need:
SELECT CASE WHEN EXISTS (
SELECT *
FROM [User]
WHERE UserID = 20070022
)
THEN CAST(1 AS BIT)
ELSE CAST(0 AS BIT) END
...
How to pip install a package with min and max version range?
I'm wondering if there's any way to tell pip, specifically in a requirements file, to install a package with both a minimum version ( pip install package>=0.2 ) and a maximum version which should never be installed (theoretical api: pip install package<0.3 ).
...
How do you list the active minor modes in emacs?
... (mapc (lambda (mode) (condition-case nil
(if (and (symbolp mode) (symbol-value mode))
(add-to-list 'active-modes mode))
(error nil) ))
minor-mode-list)
(message "Active modes are %s" active-mod...
Case insensitive comparison of strings in shell script
...
if you have bash
str1="MATCH"
str2="match"
shopt -s nocasematch
case "$str1" in
$str2 ) echo "match";;
*) echo "no match";;
esac
otherwise, you should tell us what shell you are using.
alternative, using awk
str1="MATC...
Delete everything in a MongoDB database
...
Use with caution: if you're in a sharded environment using wiredTiger and you have no user database and you invoke dropDatabase, the database will be deleted and could re-appear as primary on a different shard when new records are added.
...
Why does Math.Round(2.5) return 2 instead of 3?
...age - it doesn't decide how Math.Round is implemented.
And secondly, no - if you read the docs, you'll see that the default rounding is "round to even" (banker's rounding):
Return ValueType: System.DoubleThe integer nearest a. If the
fractional component of a is halfway
between two integers...