Teamqueue(UVA 540) ansi c not so fast approach

TeamQueue.c

/**
  * UVA 540 resolution: https://uva.onlinejudge.org/index.php?option=onlinejudge&page=show_problem&problem=481
  **/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_TEAMS 1001
#define MAX_ELEMENTS 1000001
#define MAX_COMMAND_BUFFER 255
#define free( n ) free( (void*) n ), n = NULL

typedef struct __queue_element__ {
	int element;
	struct __queue_element__ *next;
} QueueElement;

typedef struct __queue__ {
	int size;
	QueueElement *head;
	QueueElement *tail;
} Queue;

Queue *queueList[MAX_TEAMS];
Queue *teamOrder;
int teams[MAX_ELEMENTS];

Queue *initQueue()
{
	Queue *newQueue = malloc( sizeof( Queue ) );
	newQueue->head = newQueue->tail = NULL;
	newQueue->size = 0;
	return newQueue;
}

void push( int element, Queue *queue )
{
	QueueElement *queueElement = malloc( sizeof( QueueElement ) );
	queueElement->element = element;
	queueElement->next = NULL;
	
	if( queue->head == NULL )
	{
		queue->tail = queue->head = queueElement;
	}
	else
	{
		queue->tail->next = queueElement;
		queue->tail = queueElement;
	}
	++queue->size;
}

void enqueue( int element )
{
	int team = teams[element];
	
	if( queueList[team]->size == 0 )
	{
		push( team, teamOrder );
	}
	push( element, queueList[team] );
}

int pop( Queue *queue )
{
	int element = -1;

	if( queue->size != 0 )
	{
		QueueElement *elem = queue->head;
		queue->head = elem->next;
		element = elem->element;
		free( elem );
		--queue->size;
	}

	return element;
}

int dequeue()
{
	int element = -1;

	if( teamOrder->head != NULL )
	{
		int team = teamOrder->head->element;

		element = pop( queueList[team] );
		
		if( queueList[team]->size == 0 )
		{
			pop( teamOrder );
		}
	}
	
	return element;
}

void clear()
{
	while( dequeue() != -1 );
	while( pop( teamOrder ) != -1 );
}

int
main()
{
	int nTeams;
	int currentScenario = 1;
	char command[MAX_COMMAND_BUFFER];

	teamOrder = initQueue();
	
	int i = 0;
	for( ; i < MAX_TEAMS ; ++i )
	{
		queueList[i] = initQueue();
	}
	
	scanf( "%d", &nTeams );
	while( nTeams != 0 )
	{
		clear();
		int i;
		for( i = 0 ; i < nTeams ; ++i )
		{
			int nElements = 0;
			scanf( "%d", &nElements );
			while( nElements-- )
			{
				int element;
				scanf( "%d", &element );
				teams[element] = i;
			}
		}

		printf( "Scenario #%d\n", currentScenario );
		command[0] = '\0';
		while( *command != 'S' )
		{
			if( *command == 'E' )
			{
				int element = 0;
				scanf( "%d", &element );
				enqueue( element );
			}
			else if ( *command == 'D' )
			{
				int element = dequeue();
				printf( "%d\n", element );
			}
			scanf( "%s", command );
		}
		putchar( '\n' );
		++currentScenario;
		scanf( "%d", &nTeams );
	}
	
	clear();
	free( teamOrder );

	for( i = 0 ; i < MAX_TEAMS ; ++i )
	{
		free( queueList[i] );
	}
	
	return 0;
}