A sparse array can be represented as a vector of rows, with each row represented as a list of nondefault column entries. Thus, the nondefault entry at  would appear as an element of list R. The element would contain both its column identification (j) and the nondefault entry .

(a) Express the table shown in Figure 5.20 using this format.

(b) Compare the effectiveness of this representation with those given in Section 5.8. Consider both the savings in space and any increase or decrease in access time.

Figure 5.20