#include <stdio.h>

#define MAXLINE 1000

static struct buf_entry {
	float s_time;
	int p_id;
	struct buf_entry *next;
} *head, *tail;

void init_buf()
{
head = tail = NULL;
}

void insert_buf(float time_id, int packet_id)
{
struct buf_entry *entry;

entry = (struct buf_entry *) malloc(sizeof(struct buf_entry));
entry->s_time = time_id;
entry->p_id = packet_id;
entry->next = NULL;

if (head == NULL) {
	head = tail = entry;
}
else {
	tail->next = entry;
	tail = entry;
}
	
}

// find the matching entry with the given packet_id
// return the sent time of the packet
float remove_buf(int packet_id)
{
struct buf_entry *np, *old_np;
float save_time;

if (head->p_id == packet_id) {
	np = head;
	save_time = np->s_time;
	if (head == tail) head = tail = NULL;
	else head = np->next;
	free(np);
	return(save_time);
}

for (np = head; np != NULL; np = np->next) {
	if (np->p_id == packet_id) {
		save_time = np->s_time;
		old_np->next = np->next;
		if (tail == np) tail = old_np;
		free(np);
		return(save_time);
	}
	old_np = np;
}
return(0.0);
}

// count the number of packets that are not received yet
int check_buf(float last_receive_time)
{
int count;
struct buf_entry *np;

for (count = 0, np = head; np != NULL; np = np->next)
	if (np->s_time<last_receive_time) count++;

return(count);
}

main(int argc, char *argv[])
{
char line[MAXLINE];
FILE *fp, *fopen();
char sr;
int packet_id, old_packet_id, success, dropped, remain, re_received;
float time_id, old_time_id, total_delay, sent_time, last_time;

old_packet_id = 0;
success = 0;
dropped = 0;
total_delay = 0.0;
init_buf();
last_time = 0.0;
re_received = 0;

while (fgets(line, MAXLINE, stdin) != NULL) {
	// parse line -> char sr, float time_id, int packet_id
	sscanf(line, "%c\t%f\t%d", &sr, &time_id, &packet_id);

	// if receive, check the buffer for mathching 's'
	//	calculate the delay, update total_delay
	//	delete the matching 's' entry from the buffer
	if (sr == 'r') {
		if ((sent_time = remove_buf(packet_id)) == 0.0) {
			re_received ++;
		}
		else if (sent_time >= time_id) {
			printf("sent time is later than receiving time...\n");
			exit(1);
		}
		else {
total_delay += (time_id - sent_time);
			success ++;
		}

		if (time_id>last_time) last_time = time_id;
	}

	// if send, insert to the buffer
	// if the packet_id > last send's packet_id+1, 
	// then, dropped += packet_id - old_packet_id
	else if (sr == 's') {
		insert_buf(time_id, packet_id);
		dropped += (packet_id - old_packet_id - 1);
		old_packet_id = packet_id;
	}

	else {
		printf("it's neither s nor r...\n");
		exit(1);
	}
	
}

remain = check_buf(last_time);

// we have 'success' packets successful, 'dropped' packets dropped, 'remain' packets remained in buffer
// for successful packets, delay is total_delay/success

printf("Success:\t%d\tPDR:\t%f\tDelay:\t%f\n", 
	success, (float)success/(success+remain), total_delay/success);
}