UVa-133-The Dole Queue

AOAPC I: Beginning Algorithm Contests (Rujia Liu) :: Volume 2. Data Structures :: Lists

// 133 - The Dole Queue
#include <cstdio>
#include <cstdlib>

typedef struct node
{
	int num;
	struct node* pre;
	struct node* next;
}*ptr;

ptr creatnode(int elem)
{
	ptr temp;
	temp = (struct node*)malloc(sizeof(struct node));
	if(temp == NULL)
		exit(EXIT_FAILURE);
	temp->num = elem;
	temp->pre = NULL;
	temp->next = NULL;
	return temp;
}

void creatlist(ptr* x, ptr* y, int n)
{
	ptr head, temp;
	head = creatnode(1);
	temp = head;
	for(int i = 2; i <= n; i++)
	{
		temp->next = creatnode(i);
		temp->next->pre = temp;
		temp = temp->next;
	}
	temp->next = head;
	head->pre = temp;

	*x = head;
	*y = temp;
}

void deletenode(ptr t)
{
	ptr temp = t;
	temp->next->pre = t->pre;
	temp->pre->next = t->next;
	printf("%3d", t->num);
	free(t);
}

int main(void)
{
	int i, n, k, m, cnt;
	ptr x, y, x_t, y_t;
	while(scanf("%d%d%d", &n, &k, &m) && n)
	{
		cnt = 0;
		creatlist(&x, &y, n);

		while(cnt != n)
		{
			for(i = 1; i < k; i++)
				x = x->next;
			for(i = 1; i < m; i++)
				y = y->pre;

			if(x == y)
			{
				x_t = x->next;
				y_t = y->pre;
				deletenode(x);
				cnt++;
			}
			else if(x->next == y)
			{
				x_t = y->next;
				y_t = x->pre;
				deletenode(x);
				deletenode(y);
				cnt += 2;
			}
			else
			{
				x_t = x->next;
				y_t = y->pre;
				deletenode(x);
				deletenode(y);
				cnt += 2;
			}
			x = x_t;
			y = y_t;

			if(cnt != n)
				printf(",");
		}
		printf("\n");
	}
	return 0;
}