快排----数据结构与算法分析

/*************************************************************************
	> File Name: quicksort.cpp
	> Author:keson 
	> Mail:keson@bupt.edu.cn 
	> Created Time: 2014年12月02日 星期二 10时34分01秒
 ************************************************************************/


#include<iostream>
#include<vector>
#include<algorithm>
#include<fstream>
using namespace std;

template <typename Comparable>
void insertionSort( vector<Comparable> & a, int left, int right  )
{
        for( int p = left + 1; p <= right; ++p  )
    {
        Comparable tmp = std::move( a[p]  );
        int j;
        for( j = p; j > left && tmp < a[j-1]; --j)
            a[j] = std::move( a[j-1]);
        a[j] = std::move( tmp  );
            
    }

}





template <typename Comparable>
const Comparable &median3(vector<Comparable> &a,int left,int right)
{
    int center=(left+right)/2;

    if(a[center]<a[left])
       std::swap(a[left],a[center]);

    if(a[right]<a[left])
       std::swap(a[left],a[right]);

    if(a[right]<a[center])
       std::swap(a[center],a[right]);

    std::swap(a[center],a[right-1]);
    return a[right-1];
}

template<typename Comparable>
void quicksort(vector<Comparable> &a,int left,int right)
{
    if(left+10<=right)
    {
        const Comparable &pivot=median3(a,left,right);

        //Begin partitioning
        int i=left,j=right-1;
        for(; ;)
        {
            while (a[++i]<pivot){}
            while (pivot<a[--j]){}
            if(i<j)
               std::swap(a[i],a[j]);
            else 
               break;
        }
        std::swap(a[i],a[right-1]);
        quicksort(a,left,i-1);
        quicksort(a,i+1,right);
    }
    else
      insertionSort(a,left,right);


}


template<typename Comparable>
void quicksort(vector<Comparable> &a)
{
    quicksort(a,0,a.size()-1);
}


int main()
{
    vector<int> vec;
    int val;
    ifstream in;
    ofstream out;
    in.open("NUMBER_FILE");
    out.open("quick_sort");
    
    while(in>>val)
       vec.push_back(val);
    
    cin.clear();
    
    clock_t start_time=clock();  
    quicksort(vec);
    clock_t end_time=clock();  
    cout<<"Running time is:"<<  
    static_cast<double>(end_time-start_time)/CLOCKS_PER_SEC<<" S"<<endl;  
    cout<<endl;
    for(auto c:vec)
       out<<c<<" ";
    
    cout<<endl;

}