Problem E - Paintball
You are playing paintball on a 1000x1000 square field. A number
of your opponents are on the field hiding behind trees at various positions.
Each opponent can fire a paintball a certain distance in any direction.
Can you cross the field without being hit by a paintball?
Assume that the southwest corner of the field is at (0,0) and
the northwest corner at (0,1000).
Input Specification
The input contains several scenario. Each scenario consists of a line
containing n <= 1000, the number of opponents. A line follows
for each opponent, containing three real numbers: the (x,y) location
of the opponent and its firing range. The opponent can hit you with
a paintball if you ever pass within his firing range.
You must enter the field somewhere between the southwest and northwest
corner and must leave somewhere between the southeast and northeast
corners.
Output Specification
For each scenario,
if you can complete the trip, output four real numbers with two digits after the decimal place, the coordinates at which you may enter
and leave the field, separated by spaces. If you can enter and leave at several places,
give the most northerly. If there is no such pair
of positions, print the line:
IMPOSSIBLE
Sample Input
3
500 500 499
0 0 999
1000 1000 200
Output for Sample Input
0.00 1000.00 1000.00 800.00
Gordon Cormack