请问您所见过的最棒的一段代码是什么？

Question

import re, collections
def words(text): return re.findall('[a-z]+', text.lower()) 
def train(features):
    model = collections.defaultdict(lambda: 1)
    for f in features:
        model[f] += 1
    return model
NWORDS = train(words(file('big.txt').read()))
alphabet = 'abcdefghijklmnopqrstuvwxyz'
def edits1(word):
   splits     = [(word[:i], word[i:]) for i in range(len(word) + 1)]
   deletes    = [a + b[1:] for a, b in splits if b]
   transposes = [a + b[1] + b[0] + b[2:] for a, b in splits if len(b)>1]
   replaces   = [a + c + b[1:] for a, b in splits for c in alphabet if b]
   inserts    = [a + c + b     for a, b in splits for c in alphabet]
   return set(deletes + transposes + replaces + inserts)
def known_edits2(word):
    return set(e2 for e1 in edits1(word) for e2 in edits1(e1) if e2 in NWORDS)
def known(words): return set(w for w in words if w in NWORDS)
def correct(word):
    candidates = known([word]) or known(edits1(word)) or known_edits2(word) or [word]
    return max(candidates, key=NWORDS.get)
;

Peter Norvig的Spelling Corrector

Answer 1

最神奇的代码莫过于 Quake III 中不可思议的求解平方根实现方法，尤其是神奇的常量0x5f3759df

float Q_rsqrt( float number )
{
    long i;
    float x2, y;
    const float threehalfs = 1.5F;

    x2 = number * 0.5F;
    y  = number;
    i  = * ( long * ) &y;  // evil floating point bit level hacking
    i  = 0x5f3759df - ( i >> 1 ); // what the fuck?
    y  = * ( float * ) &i;
    y  = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration
    // y  = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removed

    #ifndef Q3_VM
    #ifdef __linux__
        assert( !isnan(y) ); // bk010122 - FPE?
    #endif
    #endif
    return y;
}

还有这句比较好玩的：

rm -rf /usr /lib/nvidia-current/xorg/xorg

源自 https://github.com/MrMEEE/bumblebee/c...