siftup( r, i, n )
	RecordArray r;
	int i, n;

	{ArrayEntry tempr;
	int j;
		while ( (j=2*i) <= n ) {
			if ( j<n && r[j].k < r[j+1].k ) j++;
			if ( r[i].k < r[j].k ) {
				tempr = r[j];
				r[j] = r[i];
				r[i] = tempr;
				i = j;
				}
			else	break;
			}
	};