快排

动画：http://www.tyut.edu.cn/kecheng1/site01/suanfayanshi/quick_sort.asp

#include <stdio.h>
#define swap(x,y) { int tmp; tmp = x; x = y; y = tmp;}

void quick_sort(int *a, int start, int end) //sort a[start] to a[end]
{
    if(start < end)
    {
        int i = start, j = end;
        int tmp = a[start];

        while(i < j)
        {
            while( i < j && a[j] >= tmp)
                j--;
            if(i < j) { a[i++] = a[j]; }

            while(i < j && a[i] < tmp)
                i++;
            if(i < j) { a[j--] = a[i]; }
        }

        a[i] = tmp;
        quick_sort(a, start, i - 1);
        quick_sort(a, i + 1, end);
    }
}

void print_array(int *array, int num)
{
    int i;
    for(i = 0; i < num; i++)
    {
        printf("%d ", array[i]);
    }
    printf ("\n");
}

int main()
{
    int array[10] = {2, 5, 8, 3, 1, 7, 9, 6, 0, 4};
    quick_sort(array, 0, 9);
    print_array(array, 10);
    return 0;
}