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How to prove that a problem is NP complete?
...is NP complete, you need to:
Show it is in NP
In other words, given some information C, you can create a polynomial time algorithm V that will verify for every possible input X whether X is in your domain or not.
Example
Prove that the problem of vertex covers (that is, for some graph G, does it hav...
How to create the branch from specific commit in different branch
...
If you are using this form of the branch command (with start point), it does not matter where your HEAD is.
What you are doing:
git checkout dev
git branch test 07aeec983bfc17c25f0b0a7c1d47da8e35df7af8
First, you set your HEAD to the branch d...
Use of the MANIFEST.MF file in Java
...separated from its value by a colon. The default manifest shows that it conforms to version 1.0 of the manifest specification.
The manifest can also contain information about the other files that are packaged in the archive. Exactly what file information is recorded in the manifest will depend on th...
How to encrypt/decrypt data in php?
...name, $auth_key, true);
if (hash_equals($auth, $actual_auth)) {
// perform decryption
}
See also: hash_equals()
Hashing
Storing a reversible password in your database must be avoided as much as possible; you only wish to verify the password rather than knowing its contents. If a user loses ...
What is two way binding?
...t two-way binding: while not a core feature of the framework, it can be performed quite simply using Backbone's Events though. It costs a few explicit lines of code for the simple cases; and can become quite hazardous for more complex bindings. Here is a simple case (untested code, written on the fl...
Best practices for exception management in Java or C# [closed]
... do something based on it. Or if I want to provide additional contextual information in an exception.
I use a general try catch at the application entry point, or the highest level possible. If an exception gets here I just log it and let it fail. Ideally exceptions should never get here.
I find ...
Pass arguments to Constructor in VBA
...claredId have a "global instance" that you get for free - exactly like UserForm modules (export a user form, you'll see its predeclaredId attribute is set to true).
A lot of people just happily use the predeclared instance to store state. That's wrong - it's like storing instance state in a static ...
To underscore or to not to underscore, that is the question
...ecessary.
So if you are just like .NET CoreFX team working on some performance critical, multithreaded, system level code, then it is STRONGLY SUGGESTED that you:
adhere to their coding standards and
use the underscore-notation and
don't read this answer any further
Otherwise please read on...
How to create a Custom Dialog box in android?
...;
}
});
dialog.show();
}
}
finally the form of call, on your Activity for example:
ViewDialog alert = new ViewDialog();
alert.showDialog(getActivity(), "Error de conexión al servidor");
I hope its work for you.
...
Why use apparently meaningless do-while and if-else statements in macros?
...
Note: the if(1) {...} else void(0) form is safer than the do {...} while(0) for macros whose parameters are code that is included in the macro expansion, because it doesn't alter the behavior of the break or continue keywords. For example: for (int i = 0; i &l...