BaiGang

#ifndef _VISION_PLAY_ARMV6_ATOMIC_H_
#define _VISION_PLAY_ARMV6_ATOMIC_H_

#if defined(__ARMEL__) &&  defined(__linux__)

typedef void (*LinuxKernelMemoryBarrierFunc)(void);

// Using the highly optimized device-specific memory barrier function.
inline void MemoryBarrier() {
  (*(LinuxKernelMemoryBarrierFunc)0xffff0fa0)();

BaiGang

#include <iostream>
using namespace std;                
                              
void swap(int* a, int* b) {
  int tmp = *a;                             
  *a = *b;
  *b = tmp;     
}            
            
void Perm(int m, int n, int* A) {

BaiGang

# baidu realtime hotspot
curl http://top.baidu.com/buzz.php?p=top10 \
| perl -MEncode -pi -e '$_=encode_utf8(decode(gb2312=>$_))' \
| grep "td class=\"key\"" | sed -e 's/^.*_blank\">//g' | sed -e 's/<.*$//g'

# sogou top queries
curl  http://top.sogou.com/hotword[0-3].html \
| perl -MEncode -pi -e '$_=encode_utf8(decode(gb2312=>$_))' \
| perl -ne 'chomp; my @titles = ($_ =~ /title=\".*?\"/g); for (my $i = 0; $i < scalar @titles; ++$i) {$titles[$i] =~ s/title=//; $titles[$i] =~ s/\"//g; print "$titles[$i]\n"}'

BaiGang

There is no an efficient StringBuilder class in C++ std library. std::ostringstream could be used as StringBuilder, but it is inefficient, and it use C++ iostream interface, which was proved a bad practice than printf family in C, although it is more "flexible" than printf family. Here are 2 thin wrapper for gnu asprintf family, which maybe more efficient and more readable than ostringstream.

    strbuilder.h 

// strbuilder.h

#include <stdio.h>
#include <string.h>

// This class is more simple to use, but it should be used for one-time printf

BaiGang

sub levenshtein_dist {

   my ($str1, $str2) = @_;
   my ($len1, $len2) = (length $str1, length $str2);

   if ($len1 == 0) {
       return $len2;
   }
   if ($len2 == 0) {