# Problem A: Average Speed

Problem A: Average Speed

## Problem A: Average Speed

You have bought a car in order to drive from Waterloo to a big city. The odometer on their car is broken, so you cannot measure distance. But the speedometer and cruise control both work, so the car can maintain a constant speed which can be adjusted from time to time in response to speed limits, traffic jams, and border queues. You have a stopwatch and note the elapsed time every time the speed changes. From time to time you wonder, "how far have I come?". To solve this problem you must write a program to run on your laptop computer in the passenger seat.

Standard input contains several lines of input: Each speed change is indicated by a line specifying the elapsed time since the beginning of the trip (hh:mm:ss), followed by the new speed in km/h. Each query is indicated by a line containing the elapsed time. At the outset of the trip the car is stationary. Elapsed times are given in non-decreasing order and there is at most one speed change at any given time.

For each query in standard input, you should print a line giving the time and the distance travelled, in the format below.

``````00:00:01 100
00:15:01
00:30:01
01:00:01 50
03:00:01
03:00:05 140
``````

``````00:15:01 25.00 km
00:30:01 50.00 km
03:00:01 200.00 km
``````

``````#include <stdio.h>

main(){
int hh, mm, ss, speed=0, newspeed, i, j, k, n, time = 0, now;
char buf[10000];
double dist = 0;

while (gets(buf)) {
n = sscanf(buf,"%d:%d:%d %d",&hh,&mm,&ss,&newspeed);
now = hh*3600 + mm*60 + ss;
dist += (now - time) / 3600. * speed;
time = now;
if (n == 3) printf("%02d:%02d:%02d %0.2lf km\n",hh,mm,ss,dist);
else if (n == 4) speed = newspeed;
else printf("oops!\n");
}
}``````

``````#include <stdio.h>

main(){
int hh, mm, ss, speed=0, newspeed, i, j, k, n, time = 0, now;
char buf[10000];
double dist = 0;

while (gets(buf)) {
n = sscanf(buf,"%d:%d:%d %d",&hh,&mm,&ss,&newspeed);
now = hh*3600 + mm*60 + ss;
dist += (now - time) / 3600. * speed;
time = now;
if (n == 3) printf("%02d:%02d:%02d %0.2lf km\n",hh,mm,ss,dist);
else if (n == 4) speed = newspeed;
else printf("oops!\n");
}
}``````