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Finding three elements in an array whose sum is closest to a given number
...t now you don't need the target value anymore.
Clearly, if we simply test all possible 3-tuples, we'd solve the problem in O(n3) -- that's the brute-force baseline. Is it possible to do better? What if we pick the tuples in a somewhat smarter way?
First, we invest some time to sort the array, whic...
Big-O for Eight Year Olds? [duplicate]
...ore 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 perform won't...
Should I Dispose() DataSet and DataTable?
... both implement IDisposable, so, by conventional best practices, I should call their Dispose() methods.
10 Answers
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What is reflection and why is it useful?
... say you have an object of an unknown type in Java, and you would like to call a 'doSomething' method on it if one exists. Java's static typing system isn't really designed to support this unless the object conforms to a known interface, but using reflection, your code can look at the object and fin...
How does Java handle integer underflows and overflows and how would you check for it?
... long or maybe java.math.BigInteger. The last one doesn't overflow, practically, the available JVM memory is the limit.
If you happen to be on Java8 already, then you can make use of the new Math#addExact() and Math#subtractExact() methods which will throw an ArithmeticException on overflow.
pub...
How to sort an array in descending order in Ruby
... 0.001631 0.110628 ( 0.111532)
...the reverse method doesn't actually return a reversed array - it returns an enumerator that just starts at the end and works backwards.
The source for Array#reverse is:
static VALUE
rb_ary_reverse_m(VALUE ary)
{
long len = RARRAY_LEN(...
How to use shared memory with Linux in C
... you'd rather use the old-style tools.
The mmap() function can be used to allocate memory buffers with highly customizable parameters to control access and permissions, and to back them with file-system storage if necessary.
The following function creates an in-memory buffer that a process can sha...
How to get root access on Android emulator?
I have All Android SDK versions(from 1.5 to 2.3.3), and I tried many methods for getting root in Android emulator. I don't use any Android device and test everything on emulator(AVD).
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Dialog to pick image from gallery or from camera
Is there a standard way to call dialog box with choose either to pick an image from the camera or to get from gallery (like in build-in phone book or Skype)?
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MFC RadioButton用法详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
...件定义Control变量或Value变量，每组只能定义一个）
BOOL m_Radio1;//对应于组 1 1
BOOL m_Radio3; //对应于组 2 1
BOOL m_Radio7; //对应于组 3 1
BOOL m_Radio9; //对应于组 4 1
CButton m_RBtGroup1; //对应于组 1 1
CButton m_RBtGroup2;...