Method push

chapter19/src/main/java/com/seaofnodes/simple/Ary.java:39–42

Add element in amortized constant time @param e Element to add at end of list

( E e )

     *  @param e Element to add at end of list
     **/
    public E push( E e ) {
        if( _len >= _es.length ) _es = Arrays.copyOf(_es,Math.max(1,_es.length<<1));
        return (_es[_len++] = e);
    }
    /** @return remove and return last element */
    public E pop( ) {
        return _len==0 ? null : _es[--_len];