[Solved]1 Consider Following Set Candidate 3 Itemsets 1 2 3 1 2 6 1 3 4 2 3 4 2 4 5 3 4 6 4 5 6 Co Q37159547

1. Consider the following set of candidate 3-itemsets: {1, 2,3}, {1, 2, 6}, {1, 3, 4}, {2, 3, 4}, {2, 4, 5}, {3, 4, 6}, {4, 5,6} Construct a hash tree for the above candidate 3-itemsets. Assumethe tree uses a hash function where all odd-numbered items arehashed to the left child of a node, while the even-numbered itemsare hashed to the right child. A candidate k-itemset is insertedinto the tree by hashing on each successive item in the candidateand then following the appropriate branch of the tree according tothe hash value. Once a leaf node is reached, the candidate isinserted based on one of the following conditions: Condition 1: Ifthe depth of the leaf node is equal to k (the root is assumed to beat depth 0), then the candidate is inserted regardless of thenumber of itemsets already stored at the node. Condition 2: If thedepth of the leaf node is less than k, then the candidate can beinserted as long as the number of itemsets stored at the node isless than maxsize. Assume maxsize = 2 for this question. Condition3: If the depth of the leaf node is less than k and the number ofitemsets stored at the node is equal to maxsize, then the leaf nodeis converted into an internal node. New leaf nodes are created aschildren of the old leaf node. Candidate itemsets previously storedin the old leaf node are distributed to the children based on theirhash values. The new candidate is also hashed to its appropriateleaf node. How many leaf nodes are there in the candidate hashtree? How many internal nodes are there? Consider a transactionthat contains the following items: {1, 2, 3, 5, 6}. Using the hashtree constructed in part (a), which leaf nodes will be checkedagainst the transaction? What are the candidate 3-itemsetscontained in the transaction?

Expert Answer

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Answer to 1. Consider the following set of candidate 3-itemsets: {1, 2, 3}, {1, 2, 6}, {1, 3, 4}, {2, 3, 4}, {2, 4, 5}, {3, 4, 6},… . . .