private static void merge(Comparable[] array, int begin, int mid, int end){
        // Ejercicio
                int tmpPos = begin;
                int numElements = end - begin + 1;
                Comparable[] tmpArray = new Comparable[end];

                // ciclo principal
                while( begin <= (mid -1) && mid <= end )
                        if( array[begin].compareTo( array[mid] ) <= 0 )
                          tmpArray[ tmpPos++ ] = array[begin++];
                        else
                          tmpArray[ tmpPos++ ] = array[mid++];

                while( begin <= (mid -1) )    // Copia la primera mitad
                        tmpArray[ tmpPos++ ] = array[begin++];

                while( mid <= end )  // Copia la segunda mitad
                        tmpArray[ tmpPos++ ] = array[mid++];

                // ---
                for( int i = 0; i < numElements; i++, end-- )
                        array[end] = tmpArray[end];
    }