A sorting algorithm is an algorithm that puts elements of a list in a certain order. The most-used orders are numerical order and lexicographical order What is sorting algorithm The bubble sort The selection sort The insertion sort The Quick sort The Shell Sort

1. IT 4043
Data Structures and Algorithms
Budditha Hettige
Department of Computer Science
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2. Syllabus
• Introduction to DSA
• Abstract Data Types
• Arrays
• List Operation Using Arrays
• Recursion
• Stacks
• Queues
• Link List
•Sorting
• Algorithms Analysis
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3. Sorting
• Sorting is so important and potentially so time
consuming,
• It has been the subject of extensive research in
computer science
• Algorithms for sorting
– The bubble sort,
– The selection sort,
– The insertion sort
– The Quick sort
– The Shell Sort
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4. Example
• Before
• After
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5. Bubble Sort
• Bubble sort is a simple sorting algorithm
• Compares each pair of adjacent items and swaps
them if they are in the wrong order.
• The pass through the list is repeated until no waps
are needed, which indicates that the list is sorted.
• Here are the rules you’re following:
1. Compare two items
2. If the one on the left is taller, swap them.
3. Move one position right.
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6. Example
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7. Algorithms
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8. Example
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9. Efficiency of the Bubble Sort
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10. Java Application
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11. Selection Sort
• The selection sort improves on the bubble sort by
reducing the number of swaps necessary from
O(N2) to O(N).
• Unfortunately, the number of comparisons
remains O(N2).
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12. Example
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13. Algorithms
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14. Example
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15. Efficiency of the Selection Sort
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16. Insertion Sort
• Insertion sort is a simple sorting algorithm that
builds the final sorted array (or list) one item at a
time.
• It is much less efficient on large lists than more
advanced algorithms such as quicksort, heapsort,
or merge sort.
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17. Example
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18. Insertion sort
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19. Example
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20. Efficiency of the Selection Sort
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21. Quick Sort
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22. Algorithm
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23. Shell Sort
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24. Questions
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1. Identify which of the following is/are true? In each
case justify your answer.
1. In bubble sort and selection sort give O(N2) for the
worst case.
2. Quick sort is more efficacious than the bubble sort.
2. Consider the following array with 10 elements.
Apply “Bubble sort and selection sort” algorithm to
sort this list.
List = [45,82, 25, 94, 50, 60, 78, 32, 80, 93];
3. Implement the bubble sort algorithm and
implement a Java program to sort and print 10
integer values