Suppose blocks hold either three records or ten keypointer p

Suppose blocks hold either three records, or ten key-pointer pairs. As a function of n, the number of records, how many blocks do we need to hold a data file and: (a) A dense index (b) A sparse index?

Solution

given that every 3 record need 1 block that means for n records need n/3 blocks.

Dense index:

index record appears for every search keyvalue in file.

so for n records need n/3 blocks and for key-pointers given has n/10 blocks total is=13n/30

Sparse index:

normally for data records need n/3 records. it has only key pointers to the entire block.so that bock size of key pointer and capacity of block(number of records) that means n/30 blocks for index or key-pointers. the total is 11n/30