A Practical Introduction to Data Structures and Algorithm Analysis

356 Chap. 9 Searching9.5 Implement a database stored on disk using bucket hashing. Define records tobe 128 bytes long with a 4-byte key and 120 bytes of data. The remaining4 bytes are available for you to store necessary information to support thehash table. A bucket in the hash table will be 1024 bytes long, so each buckethas space for 8 records. The hash table should consist of 27 buckets (totalspace for 216 records with slots indexed by positions 0 to 215) followed bythe overflow bucket at record position 216 in the file. The hash function forkey value K should be K mod 213. (Note that this means the last threeslots in the table will not be home positions for any record.) The collisionresolution function should be linear probing with wrap-around within thebucket. For example, if a record is hashed to slot 5, the collision resolutionprocess will attempt to insert the record into the table in the order 5, 6, 7, 0,1, 2, 3, and finally 4. If a bucket is full, the record should be placed in theoverflow section at the end of the file.Your hash table should implement the dictionary ADT of Section 4.4. Whenyou do your testing, assume that the system is meant to store about 100 or sorecords at a time.9.6 Implement the dictionary ADT of Section 4.4 by means of a hash table withlinear probing as the collision resolution policy. You might wish to beginwith the code of Figure 9.7. Using empirical simulation, determine the costof insert and delete as α grows (i.e., reconstruct the dashed lines of Figure9.8). Then, repeat the experiment using quadratic probing and pseudorandomprobing. What can you say about the relative performance of thesethree collision resolution policies?