1. Searching Chapter 13 Objectives Upon completion you will be able to:
Design and implement sequential searches
Discuss the relative merits of different sequential searches
Design and implement binary searches
Design and implement hash-list searches
Discuss the merits of different collision resolution algorithms
Data Structures: A Pseudocode Approach with C, Second Edition

2. 13-1 List Searches Sequential Search Variations on Sequential Searches
In this section we study searches that work with arrays. The two basic searches for arrays are the sequential search and the binary search.
Sequential Search
Variations on Sequential Searches
Binary Search
Analyzing Search Algorithms
Data Structures: A Pseudocode Approach with C, Second Edition

3. Searching
The process used to find the location of a target among a list of objects.
Data Structures: A Pseudocode Approach with C, Second Edition

4. List searches Sequential search Variations of sequential search
Sentinel search
Probability search
Ordered list search
Binary search
Data Structures: A Pseudocode Approach with C, Second Edition

5. Sequential search
The sequential search is used whenever the list is not ordered.
Data Structures: A Pseudocode Approach with C, Second Edition

6. Successful search of an unordered list
Data Structures: A Pseudocode Approach with C, Second Edition

7. Unsuccessful search in unordered list
Data Structures: A Pseudocode Approach with C, Second Edition

8. Sequential search algorithm
Data Structures: A Pseudocode Approach with C, Second Edition

9. Variations on sequential searches
Sentinel search
Probability search
The data in the array are arranged with the most probable search elements at the beginning of the array and the least probable at the end.
Ordered list search
Data Structures: A Pseudocode Approach with C, Second Edition

10. Sentinel search algorithm
Data Structures: A Pseudocode Approach with C, Second Edition

11. Probability search algorithm
Data Structures: A Pseudocode Approach with C, Second Edition

12. Ordered list search algorithm
Data Structures: A Pseudocode Approach with C, Second Edition

13. Binary search The list must be sorted.
The list starts to become large.
Contains more than 16 elements.
mid = (begin + end) / 2
Data Structures: A Pseudocode Approach with C, Second Edition

14. Binary search example
Data Structures: A Pseudocode Approach with C, Second Edition

15. Unsuccessful binary search example
Figure 2-5
Unsuccessful binary search example
Data Structures: A Pseudocode Approach with C, Second Edition

16. Data Structures: A Pseudocode Approach with C, Second Edition

17. (continued)
Data Structures: A Pseudocode Approach with C, Second Edition

18. Analyzing search algorithms
The efficiency of the sequential search is O(n).
The efficiency of the binary search is
O(log n).
List size
Iterations
binary
sequential 16 4 50 6
256 8
1000 10
10000 14
100000 17 20
Data Structures: A Pseudocode Approach with C, Second Edition

19. 13-2 Search Implementations
Having discussed the basic concepts of array searches, we write C implementations of the two most common.
Sequential Search in C
Binary Search In C
Data Structures: A Pseudocode Approach with C, Second Edition

20. Sequential Search in C
Data Structures: A Pseudocode Approach with C, Second Edition

21. Data Structures: A Pseudocode Approach with C, Second Edition

22. Binary Search In C
Data Structures: A Pseudocode Approach with C, Second Edition

23. Data Structures: A Pseudocode Approach with C, Second Edition