OJ Board

The output specification for Polygon Visibility is WRONG!!!!
You should output a colon (:) after the instance name.
The sample output should be:

Instance 1:
VERTICAL
10 20
20 20
20 10
0.000
Instance 2:
1.000
15 15
20 19
25 15
20 10
-1.000

Also, you should never output -0.000. Output 0.000 ...