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Best way to represent a fraction in Java?
...too long ago, for Project Euler problems. It keeps a BigInteger numerator and denominator, so it'll never overflow. But it'll be a tad slow for a lot of operations that you know will never overflow.. anyway, use it if you want it. I've been dying to show this off somehow. :)
Edit: Latest and gre...
Swift Beta performance: sorting arrays
I was implementing an algorithm in Swift Beta and noticed that the performance was very poor. After digging deeper I realized that one of the bottlenecks was something as simple as sorting arrays. The relevant part is here:
...
Get index of array element faster than O(n)
Given I have a HUGE array, and a value from it. I want to get index of the value in array. Is there any other way, rather then call Array#index to get it? The problem comes from the need of keeping really huge array and calling Array#index enormous amount of times.
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How to create a HashMap with two keys (Key-Pair, Value)?
...= 31 * result + y;
return result;
}
}
Implementing equals() and hashCode() is crucial here. Then you simply use:
Map<Key, V> map = //...
and:
map.get(new Key(2, 5));
Table from Guava
Table<Integer, Integer, V> table = HashBasedTable.create();
//...
table.get(2, 5);...
Obtaining a powerset of a set in Java
...2^n possible combinations. Here's a working implementation, using generics and sets:
public static <T> Set<Set<T>> powerSet(Set<T> originalSet) {
Set<Set<T>> sets = new HashSet<Set<T>>();
if (originalSet.isEmpty()) {
sets.add(new HashS...
python location on mac osx
...if the previous owner of the laptop has installed macpython using macport. And I remembered that osx has an builtin version of python. I tried using type -a python and the result returned
...
How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
...ow about accesing data from one structure vs the other? I'm thinking cache and location
– Horia Toma
Apr 14 '14 at 22:38
9
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Comparing two dictionaries and checking how many (key, value) pairs are equal
...
Maybe something like this:
shared_items = {k: x[k] for k in x if k in y and x[k] == y[k]}
print len(shared_items)
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Installing R on Mac - Warning messages: Setting LC_CTYPE failed, using “C”
...e runs R in a docker environment (under root), try to run R with below command,
LC_ALL=C.UTF-8 R
# instead of just `R`
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Disable assertions in Python
... process that uses or inherits the environment.
E.g., in Windows, setting and then clearing the environment variable:
C:\>python -c "assert False"
Traceback (most recent call last):
File "<string>", line 1, in <module>
AssertionError
C:\>SET PYTHONOPTIMIZE=TRUE
C:\>python -...