lecture 6 data structures
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Lecture 6 Data Structures
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Priority Queue• A priority queue is a data structure for
maintaining a set of elements, each with an associated value, called a key.
• A max-priority queue supports the following operations: Insert(S,x), Maximum(S),
Extract-Max(S), Increase-Key(S,x,k).• Max-Heap can be used for implementing max-priority queue.
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Doubly Linked List
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Sentinel• A sentinel is a dummy object that allow us to
simplify the boundary condition.• With sentinel, a doubly linked list can be
turned into a circular one. • The sentinel nil[L] is placed between the head
and the tail.
][Lnil
];[]][[ ];[]][[
),(Delete-List
xprevxnextprevxnextxprevnext
xL
Direct Addressing• Direct addressing is a simple technique
that work well when the universe of keys is reasonably small.
• Direct-address table is an array in which each position, or slot, corresponds to a key in the universe.
• If the universe is large, how to do?• Hashing!
Hash Table• Collision resolution by chaining
Hash Functions
)1mod()(.mod)(
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What we learnt in this lecture?
• Review elementary data structures
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