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Java regex email
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Just two counterexamples: webmaster@müller.de (valid and rejected by your example), matteo@78.47.122.114 (my email, valid and rejected by your example.
– Matteo
Nov 21 '11 at 5:58
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Fastest way to list all primes below N
...t William Hanks for primesfrom2to, primesfrom3to, rwh_primes, rwh_primes1, and rwh_primes2.
Of the plain Python methods tested, with psyco, for n=1000000,
rwh_primes1 was the fastest tested.
+---------------------+-------+
| Method | ms |
+---------------------+-------+
| rwh_prime...
How to find time complexity of an algorithm
...chine instructions it will execute as a function of the size of its input, and then simplify the expression to the largest (when N is very large) term and can include any simplifying constant factor.
For example, lets see how we simplify 2N + 2 machine instructions to describe this as just O(N).
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Schema for a multilanguage database
...es, localizability is not an issue. We can use language specific resources and have all kinds of tools that work well with them.
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How can building a heap be O(n) time complexity?
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Often, answers to these questions focus on the difference between siftUp and siftDown. Making the correct choice between siftUp and siftDown is critical to get O(n) performance for buildHeap, but does nothing to help one understand the difference between buildHeap and heapSort in general. Indeed, ...
Big-O for Eight Year Olds? [duplicate]
I'm asking more about what this means to my code. I understand the concepts mathematically, I just have a hard time wrapping my head around what they mean conceptually. For example, if one were to perform an O(1) operation on a data structure, I understand that the number of operations it has to p...
How to create the most compact mapping n → isprime(n) up to a limit N?
...test, you should probably run a probabilistic test since those are faster, and then follow it up with a deterministic test to make sure the number is prime.
You should know that the math behind the fastest algorithms is not for the faint of heart.
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What is a plain English explanation of “Big O” notation?
I'd prefer as little formal definition as possible and simple mathematics.
41 Answers
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Designing function f(f(n)) == -n
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Hmm, saving state with even and odd numbers, I should've thought of that.
– Unknown
Apr 8 '09 at 22:25
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Memoization in Haskell?
...f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate results.
But it still takes linear time just to index to find the memoized answer for mf. This means that results like:
*Main Dat...