1995 ACM South Central Region 
Programming Contest 
 
Problem #5: Radar Scopes 
 
Source File: radar.pas 
             radar.cpp 
             radar.bas 
           radar.c 
Input File: radar.in 
Output File: radar.out 
 
You have been hired to a team of software designers to write a new air-
traffic control system.  One of the functions of this new software is 
to automatically verify the functioning of the subject aircrafts' 
instrumentation and alert controllers to endangered, newly aloft, or 
possibly downed aircraft.  You are to write a prototype of this 
function. 
 
Your program will be given a series of scenarios which include 2 radar 
sweeps each.  Each radar sweep will find 0 to 100 airplanes.  Each time 
a sweep encounters a plane, the data acquisition system captures an 
azimuth reading and distance (in miles) from the radar.  It will also 
retrieve (from the plane) a squawk number and a ground speed in 
miles/hour (actually an airspeed with wind corrections).  Based on the 
two radar sweeps, your program is to determine if a warning is required 
for any plane in the radar's domain. 
 
You should assume a radar range (radius of the area covered) of 10 
miles and instantaneous sweeps that occur 5 seconds apart. 
 
Based on the information about the radar and planes, you are to 
determine if the controllers should be warned of potential problems. 
 
An "equipment warning" is issued if the average of the plane's two 
indicated airspeeds is not within 10% of the airspeed 
measured/calculated based on radar sweeps. 
 
A "new intrusion" warning is issued if the second radar sweep indicates 
a plane which was not present in the first sweep, but whose indicated 
airspeed + 10% is sufficient to have brought the plane onto the scope 
(on the shortest path) between the two sweeps.  If the speed is not 
sufficient to account for a plane which was already aloft, then the 
assumption must be made that there is a "new aloft" warning to be 
issued because a plane has just taken off within the domain of the 
radar. 
 
A "domain exited" warning is issued if the first sweep of the radar 
indicates a plane which is not seen in the second sweep but whose 
indicated airspeed + 10% is sufficient to have accounted for the plane 
leaving the range of the radar (on the shortest path) within the two 
sweeps.  If the speed is not sufficient to allow the plane to leave the 
radar scope between the sweeps, a "domain loss" warning is issued 
indicating that the plane has either landed or crashed with the 
controller's domain. 
 
Input 
The first line of each scenario contains a single integer (0<=N1<=100) 
that indicates the number of planes detected in the first sweep.  The 
next N1 lines each contain the description of exactly one detected 
plane in sweep 1.  Each description contains a squawk number, an 
azimuth, a distance, and a ground speed.  The squawk number is an 
integer between 1 and 5 digits in length.  The azimuth, distance and 
ground speed are all real numbers in the format XXX.XXX with leading 
and trailing zeroes as needed to fill all 6 places. 
 
The squawk number (0<S<32767) is a globally unique integer that 
identifies each plane and is used to match planes from sweeps 1 and 2.  
The azimuth (000.000<=A<=359.999) is the angle in degrees from North 
(sweeping in a circle toward the East) where the plane was detected.  
Therefore, East is at 90 degrees; South is at 180 degrees; and West is 
at 270 degrees.  The distance (000.000<=D<=010.000) is the distance 
from the radar to the plane (added distance due to altitude has been 
removed by the radar's sensing logic).  The ground speed 
(000.000<=G<=999.999) is the speed at which the plane is moving (in any 
direction) relative to the radar. 
 
Immediately following the lines with the descriptions of planes in the 
first sweep is a line with a single integer (0<=N2<=100) indicating the 
number of planes detected in the second sweep.  The next N2 lines each 
contain the description of exactly one detected plane in sweep 2. 
 
The next scenario (if any) starts with N1 on the next line.  You are to 
read and process scenarios to the end-of-file. 
 
Output 
For each scenario, you are to print "Scenario # X" where X is the 
number of the scenario starting with 1 for the first scenario and 
incrementing by 1 for successive scenarios.  Each subsequent line 
contains exactly one report for each plane requiring a warning 
indication.  These lines are to be sorted based on the squawk number.  
Reports consist of the squawk number right-justified in columns 1 to 5 
and one of the following warnings " -- equipment warning", " -- new 
intrusion", " -- new aloft", " -- domain exited", or " -- domain loss" 
starting in column 6.  (You must print the blanks and dashes exactly as 
shown in the strings above.)  There are no messages printed for planes 
for whom no warning applies. 
 
After each scenario, print a blank line. 
 
Sample Input 
4 
222   060.111   007.600   095.000 
1496  203.122   009.444   598.991 
111   000.000   005.100   999.999 
013   333.333   006.711   188.448 
4 
111   001.000   003.713   999.999 
777   263.122   009.933   477.633 
333   083.014   004.300   127.122 
222   040.713   009.813   098.125 
 
Sample Output 
Scenario # 1 
013 -- domain loss 
222 -- equipment warning 
333 -- new aloft 
777 -- new intrusion 
1496 -- domain exited