算法-QuickSort

#include <stdlib.h>
#include <iostream>
#include <vector>

using namespace std;

template <class T>
void print_array(const vector<T> &array)
{
    for ( unsigned int i = 1; i < array.size() + 1; ++i )
    {
        cout<<array[i-1]<<" ";
        if ( array[i - 1] < 10 )
            cout<<" ";
        if ( i % 10 == 0 )
            cout<<endl;
    }
}

template <class T>
void shuffling(vector<T> &array)
{
    int n = array.size();
    for ( int i = 0; i < n; ++ i )
    {        
        int r = i == 0 ? 0 : rand() % i;
        T temp = array[i];
        array[i] = array[r];
        array[r] = temp;
    }

    return;
}

template <class T>
unsigned int partition(vector<T> &array, unsigned int lo, int unsigned hi)
{
    if ( lo == hi ) return lo;

    unsigned int i = lo;
    unsigned int j = hi;
    T partition_val = array[lo];

    while ( i < j )
    {
        while ( array[i] <= partition_val )
        {
            if ( i < hi ) ++i;
            else break;
        }

        while ( array[j] > partition_val )
        {
            if ( j > lo ) --j;
            else break;
        }

        if ( i < j )
        {
            T temp = array[i];
            array[i] = array[j];
            array[j] = temp;
        }

    }

    array[lo] = array[j];
    array[j] = partition_val;

    return j;
}

template <class T>
void quick_sort(vector<T> &array, unsigned int  lo, unsigned int  hi)
{
    if ( lo >= hi ) return;
    int partition_pos = partition(array, lo, hi);
    quick_sort(array, lo, partition_pos);
    quick_sort(array, partition_pos + 1, hi);

    return;
}

int main()
{
    vector<int> array;
    for ( int i = 0; i < 20; ++i )
        array.push_back(i);

    cout<<"shuffling the array..."<<endl;
    shuffling(array);

    cout<<"the shuffled array: "<<endl;
    print_array(array);

    cout<<"quick sort the array: "<<endl;
    quick_sort(array, 0, array.size() - 1);

    cout<<"array after quick sorted: "<<endl;
    print_array(array);

    return 0;
}

输出结果：