大约有 45,000 项符合查询结果（耗时：0.0328秒） [XML]
How many random elements before MD5 produces collisions?
...housand 456.
However if you keep all the hashes then the probability is a bit higher thanks to birthday paradox. To have a 50% chance of any hash colliding with any other hash you need 264 hashes. This means that to get a collision, on average, you'll need to hash 6 billion files per second for 100...
Capturing Groups From a Grep RegEx
... to first reduce your line to a known format, and then to extract just the bit you want. (Although tools like cut and sed are far better at this).
Suppose for the sake of argument that your pattern was a bit simpler: [0-9]+_([a-z]+)_ You could extract this like so:
echo $name | grep -Ei '[0-9]+_[a...
std::vector performance regression when enabling C++11
... ( +- 2.05% )
Indeed, if we ask the compiler to try just a little bit harder to inline that function, the difference in performance goes away.
So what is the take away from this story? That failed inlines can cost you a lot and you should make full use of the compiler capabilities: I can...
0.1 float is greater than 0.1 double. I expected it to be false [duplicate]
...the rounding mode when converting the double to float. float has 24 binary bits of precision, and double has 53. In binary, 0.1 is:
0.1₁₀ = 0.0001100110011001100110011001100110011001100110011…₂
^ ^ ^ ^
1 10 20 24
So if we round up ...
Fundamental difference between Hashing and Encryption algorithms
...I'll do my best here:
Hash Functions
They provide a mapping between an arbitrary length input, and a (usually) fixed length (or smaller length) output. It can be anything from a simple crc32, to a full blown cryptographic hash function such as MD5 or SHA1/2/256/512. The point is that there's a o...
How to check the version before installing a package using apt-get?
...
10 Answers
10
Active
...
How to set custom favicon in Express?
...0/favicon.ico returns Cannot GET /favicon.ico.
– user1063287
Sep 20 at 3:23
...
“f” after number
...jective-C; putting an f on the end - 0.0f - declares the constant as a (32-bit) float.)
CGRect frame = CGRectMake(0, 0, 320, 50);
uses ints which will be automatically converted to floats.
In this case, there's no (practical) difference between the two.
...
What does |= (ior) do in Python?
... an update operation
counters: a union (of multisets) operation
numbers: a bitwise OR, binary operation
In most cases, it is related to the | operator. See examples below.
Sets
For example, the union of two assigned sets s1 and s2 share the following equivalent expressions:
>>> s1 = s1 | ...
Why are unnamed namespaces used and what are their benefits?
... then you said 3 vs 4 seconds are "the same time". neither of these make a bit of sense. i suspect the real explanation would, but what is it?
– underscore_d
Dec 25 '15 at 2:13
...