算法2.12--堆排序算法(HeapSort)

#include
#include
#include

#define MAX_LENGTH 100

/*Show usage*/
void usage(char * prog)
{
        printf("%s Usage:\n", prog);
        printf("%s \n", prog);
}

/*Generate and initialize the list*/
int * generate_list(int count)
{
        int i;
        int * list;
        list = (int *)malloc(count*sizeof(int));
        if(list == NULL)
        {
                perror("malloc");
                return NULL;
        }

        /*Initialize the list with integers less than 100*/
        srandom((unsigned int)time(NULL));
        for (i  = 0; i < count ; i ++)
                list[i] = random()%100;

        return list;
}

/*Show the list*/
void show_list(int * list, int length)
{
        int i;
        for(i = 0; i < length; i ++)
                printf("%d      ", list[i]);

        printf("\n");
}

/*algorithm*/
void fix_heap(int * list, int h_size, int root, int k)
{
        int larger;
        if((2*root +1) > h_size)
                list[root] = k;
        else
        {
                if((2*root +1) == h_size)
                {
                        larger = 2 * root +1;
                }
                else if(list[2*root+1] > list[2*root +2])
                {
                        larger = 2 * root +1;
                }
                else
                {
                        larger = 2 * root +2;
                }

                if(k > list[larger])
                        list[root] = k;
                else
                {
                        list[root] = list[larger];
                        fix_heap(list, h_size, larger, k);
                }
        }
        return;
}

void build_heap(int * list, int length)
{
        int i;
        for(i = (length+1)/2; i >= 0; i --)
                fix_heap(list, length, i, list[i]);
        return;
}

void heap_sort(int * list, int length)
{
        int i;
        build_heap(list, length - 1);

        for(i = length -1; i >= 1; i --)
        {
                int temp = list[i];
                list[i] = list[0];
                fix_heap(list, i -1, 0, temp);
        }
}

int main(int argc, char * argv[])
{
        int length;
        int * list = NULL;

        /*Deal with the arguments*/
        if(argc != 2)
        {
                usage(argv[0]);
                exit(127);
        }

        length = atoi(argv[1]);
        if(!length || length > MAX_LENGTH)
        {
                usage(argv[0]);
                exit(129);
        }

        list = generate_list(length);
        if(list == NULL)
                exit(128);
        else
        {
                printf("Soruce list:\n");
                show_list(list, length);

                heap_sort(list, length);

                printf("Ordered list:\n");
                show_list(list, length);
        }

        free(list);
        return 1;
}