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Introductory Algorithms. Lecture 01: Sorting Algorithms April 8 th , 2009 Jonathan Tse. Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up. Sort Playing Cards. Sorting Order Sort into Suits Clubs, Diamonds, Hearts, Spades Sort Suits - PowerPoint PPT Presentation
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Introductory Algorithms
Lecture 01: Sorting AlgorithmsApril 8th, 2009Jonathan Tse
Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Sort Playing Cards
• Sorting Order– Sort into Suits• Clubs, Diamonds, Hearts, Spades
– Sort Suits• A 2 3 4 5 6 7 8 9 10 J Q K
• Rules
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
Cards In Hand Cards On Table
Sort Alone Group A Group B
Sort Together Group C Group D
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Post-Sort Discussion
• What was different about how you sorted?
• Which way was harder/more time consuming?
• Which way took up more physical space?
• Was one way clearly better than another?
• Was one way better in a given situation?
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Post-Sort Discussion
• Moving 1 Card == 1 Processor Action
• Memory Space == Physical Space
• Tradeoff Between:– Number of Processor Actions– Memory Space Used
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Insertion Sort
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
17 2245 18 12Array Space
Working Space
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Insertion Sort
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17 2245 18 12Array Space
Working Space 2323
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Insertion Sort
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Working Space
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Insertion Sort
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Insertion Sort
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Insertion Sort
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Insertion Sort
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Insertion Sort
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Done!
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Selection Sort
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1723 2245 18 12Array Space
Working Space
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Selection Sort
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Selection Sort
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Selection Sort
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Selection Sort
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Selection Sort
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Selection Sort
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Array Space
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Selection Sort
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Done!
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Merge Sort
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Array Space Working Space
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Merge Sort
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Done!
Array Space Working Space
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Radix Sort
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Done!
Wor
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Summary of Sorting Algorithms
• Insertion Sort
• Selection Sort
• Merge Sort
• Radix Sort
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Wrap-Up
• Was there anything in particular you noticed about the algorithms?
• Is one better than the other?
• In what situation is one better than the other?
• How do we objectively compare these algorithms?
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Wrap Up
• Is there some comparison metric?
• Can we quantify memory usage?
• What about execution time?
• Does the list to be sorted affect anything?
• Is there a worst case?
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
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Next Time
• Standard Metrics for Algorithm Performance
• Worst Case Analysis
4/8/09Overview – Sorting Activity – Post Sort Discussion – Sorting Algorithms – Wrap Up
