public static RangeMatrix Get(int r) {
RangeMatrix ret;
if (!dictionary.TryGetValue(r, out ret)) {
ret = new RangeMatrix(r);
dictionary.Add(r, ret);
}
return ret;
}
private RangeMatrix(RangeMatrix a) {
matrix = (bool[,])a.matrix.Clone();
}
public static RangeMatrix operator -(RangeMatrix a, RangeMatrix b) {
RangeMatrix result = new RangeMatrix(a);
for (int i = 0; i < b.matrix.GetLength(0); i++) {
for (int j = 0; j < b.matrix.GetLength(1); j++) {
if (b.matrix[i, j]) {
result.matrix[i, j] = false;
}
}
}
return result;
}
