switch (size) {
        case 0:
          return of();
        case 1:
          return new SingletonImmutableTable<>(getOnlyElement(cells));
        default:
          return RegularImmutableTable.forCells(cells, rowComparator, columnComparator);
      }
    }
  }

  ImmutableTable() {}

  @Override
  public ImmutableSet<Cell<R, C, V>> cellSet() {

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** A {@code RegularImmutableTable} optimized for dense data. */
@GwtCompatible
@Immutable(containerOf = {"R", "C", "V"})
@ElementTypesAreNonnullByDefault
final class DenseImmutableTable<R, C, V> extends RegularImmutableTable<R, C, V> {
  private final ImmutableMap<R, Integer> rowKeyToIndex;
  private final ImmutableMap<C, Integer> columnKeyToIndex;

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** A {@code RegularImmutableTable} optimized for dense data. */
@GwtCompatible
@Immutable(containerOf = {"R", "C", "V"})
@ElementTypesAreNonnullByDefault
final class DenseImmutableTable<R, C, V> extends RegularImmutableTable<R, C, V> {
  private final ImmutableMap<R, Integer> rowKeyToIndex;
  private final ImmutableMap<C, Integer> columnKeyToIndex;