Map Hash Tables and Dictionaries_Part_10

Map Hash Tables and Dictionaries_Part_10 - then the key is...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Last Updated: 06/02/12 10:23 PM CSE 2011 Prof. J. Elder - 46 - Define Step It is faster not to check if the middle element is the key. Simply continue. key 43 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 If key mid , then key is in left half. If key > mid , then key is in right half.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Last Updated: 06/02/12 10:23 PM CSE 2011 Prof. J. Elder - 47 - Make Progress The size of the list becomes smaller. 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 79 km 75 km
Background image of page 2
Last Updated: 06/02/12 10:23 PM CSE 2011 Prof. J. Elder - 48 - Exit Condition If the key is contained in the original list, then the key is contained in the sublist. Sublist contains one element. Exit 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 0 km • If the key is contained in the original list,
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: then the key is at this location. key 25 Last Updated: 06/02/12 10:23 PM CSE 2011 Prof. J. Elder - 49 - If key not in original list If the key is contained in the original list, then the key is contained in the sublist. Loop invariant true, even if the key is not in the list. If the key is contained in the original list, then the key is at this location. 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 key 24 Conclusion still solves the problem. Simply check this one location for the key. Last Updated: 06/02/12 10:23 PM CSE 2011 Prof. J. Elder - 50 - Running Time The sublist is of size n, n / 2 , n / 4 , n / 8 , ,1 Each step O(1) time. Total = O(log n) key 25 3 5 6 13 18 21 21 25 36 43 49 51 53 60 72 74 83 88 91 95 If key mid , then key is in left half. If key > mid , then key is in right half....
View Full Document

Page1 / 5

Map Hash Tables and Dictionaries_Part_10 - then the key is...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online