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Determining complexity for recursive functions (Big O notation)
...a Computer Science Midterm tomorrow and I need help determining the complexity of these recursive functions. I know how to solve simple cases, but I am still trying to learn how to solve these harder cases. These were just a few of the example problems that I could not figure out. Any help would be ...
When should I use a trailing slash in my URL?
...f the second resource as if to say, "in the same place as this one except with the following relative path". It went on to say that such relative URLs are dependent on the original URL containing a hierarchical structure against which the relative link is based, and that the ftp, http,
and file U...
In JavaScript can I make a “click” event fire programmatically for a file input element?
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You cannot do that in all browsers, supposedly IE does allow it, but Mozilla and Opera do not.
When you compose a message in GMail, the 'attach files' feature is implemented one way for IE and any browser that supports this, and then implemented another way for Firefox and those brow...
When should I use a struct rather than a class in C#?
...lass in C#? My conceptual model is that structs are used in times when the item is merely a collection of value types . A way to logically hold them all together into a cohesive whole.
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if a ngSrc path resolves to a 404, is there a way to fallback to a default?
...age is the center-piece of the application, so the broken image link makes it look like the whole thing is borked. I'd like to have another image take its place on a 404.
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Is it possible to remove inline styles with jQuery?
...g an inline style ( display:block ). I'm feeling lazy and want to override it with display:none .
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Why do this() and super() have to be the first statement in a constructor?
Java requires that if you call this() or super() in a constructor, it must be the first statement. Why?
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Ruby, !! operator (a/k/a the double-bang) [duplicate]
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In most programming languages, including Ruby, ! will return the opposite of the boolean value of the operand. So when you chain two exclamation marks together, it converts the value to a boolean.
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Android Fatal signal 11 (SIGSEGV) at 0x636f7d89 (code=1). How can it be tracked down?
...e=1 and code=2 . If the memory address was 0x00000000 , I'd have a clue it is a NullPointer.
23 Answers
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COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
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Bottom Line
Use either COUNT(field) or COUNT(*), and stick with it consistently, and if your database allows COUNT(tableHere) or COUNT(tableHere.*), use that.
In short, don't use COUNT(1) for anything. It's a one-trick pony, which rarely d...