高速分拣

#include<iostream>
#include<iterator>
#include<vector>
#include<algorithm>
#include<time.h>
using namespace std;

/*
*高速排序问题
*/
void Fast_sort(vector<int>& a,int beg,int end)
{
  if(beg+1>=end) return;
  int key = beg;
  for (int i = beg , j = end; i < j; )
  {
    if(key == i)
    {
      do
      {
        j--;
      } while (a[j]>a[key]);
      key = j;
    }else
    {
      do
      {
        i++;
      } while (a[i]<a[key]);
      key = i;
    }
    swap(a[i],a[j]);
  }
  Fast_sort(a,beg,key);
  Fast_sort(a,key+1,end);
}

int main()
{
  long start, end;
  vector<int> vec;
  copy(istream_iterator<int>(cin),istream_iterator<int>(),back_inserter(vec));
  start = clock();
  Fast_sort(vec,0,vec.size());
  end = clock();
  copy(vec.begin(),vec.end(),ostream_iterator<int>(cout," "));
  cout<<endl;
  cout <<"程序执行时间（单位：毫秒）： "<< end-start <<endl;
}