MUHAMMAD FAHMI BIN ROSLEE A21EC0285-
Clifford A. Shaffer[1997] define searching as
a process to determine whether an element is a member of a certain data set
-
External search
only implemented if searching is done on a very large size of data. Half of the data need to be processed in RAM while half of the data is in the secondary storage.
-
Internal search
searching technique that is implemented on a small size of data. All datacan be load into RAM while the searching process is conducted.
-
Basic Sequential Search
• usually to search item from unsorted list/array
• small size
• low effiecieny
• every element in array will be examine sequentially
• repeated until last element of array or until data is found
• used for searching that involves record stored in the main memory (RAM)
• simple but slowest search algorithm
-
Basic Sequential Searching Strategy
• Examines element in array sequentially and compared with the search key
• Search successful if key matches with compared value in array
• Search process terminated
• if no matches found, search continue until last element of array
• Search failed if no matches found from array
-
Sequential search drawback
Having to traverse the entire list, O(n)
-
Binary search algorithm\ Worse case
Log2 n
-
How binary search algorithm works
- search process started at the middle of the list
- then algorithm determine which half the is in
- repeat
-
Binary search best case
search key found in first middle array, O(1)
-
Worse case for binary search
search key is not in the list or searching size equal to 1
