import java.util.Comparator;

public class InsertionSort
    implements Sort
{
    private Comparator comp = null;
    
    public InsertionSort()
    {}
    
    public InsertionSort( Comparator c )
    { comp = c; }
    
    public void sort( Object [] d )
    { sort( d, 0, d.length - 1 ); }
    
    public void sort( Object [] d, int start, int end )
    {
        Object key;
        int i, j;
        
        // j indexa el elemento que se va a insertar
        // i indexa las posibles posiciones en las que se podrķa insertar el elemento j
        for ( j = start + 1; j <= end; j++ )
        {
            key = d[ j ];
            for ( i = j - 1; i >= 0 && compare( key, d[ i ] ) < 0; i-- )
                d[ i + 1 ] = d[ i ];
            d[ i + 1] = key;
        }
    }
    
    private int compare( Object a, Object b )
    {
        if ( comp == null )
        {
            return ((Comparable)a).compareTo( b );
        }
        else
        {
            return comp.compare( a, b );
        }
    }
}