Suppose you hash n items into a hash table of size k. It is natural to ask about the time it takes to find an item in the hash table. We can divide this into two cases, one when the item is not in the hash table (an unsuccessful search), and one when the item is in the hash table (a successful search). Consider first the unsuccessful search. Assume the keys hashing to the same location are stored in a list with the most recent arrival at the beginning of the list. Use our expected list length to bound the expected time for an unsuccessful search. Next consider the successful search. Recall that when we insert items into a hash table, we typically insert them at the beginning of a list, and so the time for a successful search for item i should depend on how many entries were inserted after item
i. Carefully compute the expected running time for a successful search. Assume that the item you are searching for is randomly chosen from among the items already in the table. (Hint: The unsuccessful search should take roughly twice as long as the successful one. Be sure to explain why this is the case.)