Consider a hash table π[0, 1, β¦ , 10] that is initially empty. The hash table is
maintained using open addressing with linear probing. The hash function used is
β(π₯) = (π₯+ 7) mod 11.
Consider the following sequence of insertions performed on π:
1, 13, 22, 15, 11, 24
Which of the following positions in the hash table is/are empty after these insertions
are performed?
We have a hash table P[0..10] (11 slots) using open addressing with linear probing and hash function \(h(x) = (x+7) \bmod 11\). We insert 1, 13, 22, 15, 11, 24 in order and must find the empty slots afterward.
Step 1: Insert 1.
\(h(1) = (1+7) \bmod 11 = 8\). Slot 8 is empty, so place 1 at index 8.
Step 2: Insert 13.
\(h(13) = (13+7) \bmod 11 = 20 \bmod 11 = 9\). Slot 9 is empty, so place 13 at index 9.
Step 3: Insert 22.
\(h(22) = (22+7) \bmod 11 = 29 \bmod 11 = 7\). Slot 7 is empty, so place 22 at index 7.
Step 4: Insert 15.
\(h(15) = (15+7) \bmod 11 = 22 \bmod 11 = 0\). Slot 0 is empty, so place 15 at index 0.
Step 5: Insert 11.
\(h(11) = (11+7) \bmod 11 = 18 \bmod 11 = 7\). Slot 7 is occupied (22), so probe forward: slot 8 is occupied (1), slot 9 is occupied (13), slot 10 is empty. Place 11 at index 10.
Step 6: Insert 24.
\(h(24) = (24+7) \bmod 11 = 31 \bmod 11 = 9\). Slot 9 is occupied (13), probe slot 10 (occupied by 11), wrap around to slot 0 (occupied by 15), then slot 1 is empty. Place 24 at index 1.
Step 7: List the final table and identify empty slots.
Final table: index 0 = 15, index 1 = 24, index 2 = empty, index 3 = empty, index 4 = empty, index 5 = empty, index 6 = empty, index 7 = 22, index 8 = 1, index 9 = 13, index 10 = 11.
So the empty slots are 2, 3, 4, 5, and 6. Among the given options (0, 10, 2, 1), only index 2 is empty; indices 0, 10, and 1 are all occupied.
\[ \boxed{\text{Option C (index 2)}} \]A schedule of three database transactions \(T_1\), \(T_2\), and \(T_3\) is shown. \(R_i(A)\) and \(W_i(A)\) denote read and write of data item A by transaction \(T_i\), \(i = 1, 2, 3\). The transaction \(T_1\) aborts at the end. Which other transaction(s) will be required to be rolled back?
