/* Check hashmap for lines that are equivalent. Note that we need to check one epsilon above and below the actual slope
* since we're defining two lines as equivalent if they're within an epsilon of each other.
*/
public static int countEquivalentLines(HashMap<Double, ArrayList<Line>> linesBySlope, Line line) {
double key = Line.floorToNearestEpsilon(line.slope);
int count = countEquivalentLines(linesBySlope.get(key), line);
count += countEquivalentLines(linesBySlope.get(key - Line.epsilon), line);
count += countEquivalentLines(linesBySlope.get(key + Line.epsilon), line);
return count;
}
/* insert line into hashmap */
public static void insertLine(HashMap<Double, ArrayList<Line>> linesBySlope, Line line) {
ArrayList<Line> lines = null;
double key = Line.floorToNearestEpsilon(line.slope);
if (!linesBySlope.containsKey(key)) {
lines = new ArrayList<Line>();
linesBySlope.put(key, lines);
} else {
lines = linesBySlope.get(key);
}
lines.add(line);
}