There are several typical cube computation methods, such as MultiWay [ZDN97], BUC [BR99], and Star-Cubing [XHLW03]. Briefly describe these three methods (i.e., use one or two lines to outline the key points) and compare their feasibility and performance under the following conditions:

a. Computing a dense full cube of low dimensionality (e.g., less than eight dimensions).

b. Computing an iceberg cube of around 10 dimensions with a highly skewed data distribution.

c. Computing a sparse iceberg cube of high dimensionality (e.g., over 100 dimensions).