Algorithm and Programming (Searching)
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This file contains explanation about ssearching algorithm. This file was used in my Algorithm and Programming Class.
![Ilustration of Seq. Search Without Sentinel
Given an array to be processed:
Number
Data that want to be sought : 9
• Number[1] = 9?
• Number[2] = 9?
• Number[3] = 9?
Result: 9 is found in number[3]
5 1 9 4 2
[1] [2] [3] [4] [5]
i i + 1
i i + 1
i (STOP SEARCH)](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-9-320.jpg)
![Sequential Search Without Sentinel
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Procedure SeqSearchTanpaSentinel (Input nama_array:tipe_array)
{I.S. : elemen array [1..maks_array] sudah terdefinisi}
{F.S. : menampilkan hasil pencarian (ditemukan/tidak)}
Kamus:
i : integer
data_cari : tipedata
Algoritma:
input(data_cari)
i 1
while(nama_array [i] ≠ data_cari) and (i < maks_array) do
i i + 1
endwhile
if (nama_array[i] = data_cari)
then
output(data_cari,’ ditemukan pada indeks ke-’,i)
else
output(data_cari,’ tidak ditemukan’)
endif
EndProcedure](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-10-320.jpg)
![Ilustration of Seq. Search Use Sentinel
Data that was sought: 9
Number
Result: Data was found in Number[3]
Data that was sought: 10
Number
Result: Data was not found
5 1 9 4 2 9
[1] [2] [3] [4] [5] [6]
sentinel
5 1 9 4 2 10
[1] [2] [3] [4] [5] [6]
sentinel](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-12-320.jpg)
![Sequential Search Use Sentinel
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Procedure SeqSearchSentinel (Input nama_array:tipe_array)
{I.S. : elemen array [1..maks_array] sudah terdefinisi}
{F.S. : menampilkan hasil pencarian (ditemukan/tidak)}
Kamus:
i : integer
data_cari : tipedata
Algoritma:
input(data_cari)
i 1
nama_array(maks_array + 1) data_cari
while (nama_array [i] ≠ data_cari) do
i i + 1
endwhile
if (i < maks_array+1)
then
output(data_cari,’ ditemukan pada indeks ke-’,i)
else
output(data_cari,’ tidak ditemukan’)
endif
EndProcedure](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-13-320.jpg)
![Ilustration of Seq. Search Use Boolean
Given an array to be processed:
Number
Data that want to be sought : 9
• Number[1] = 9?
• Number[2] = 9?
• Number[3] = 9?
Result: 9 is found in number[3]
5 1 9 4 2
[1] [2] [3] [4] [5]
FOUND FALSE
FOUND FALSE
FOUND TRUE (STOP SEARCH)](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-15-320.jpg)
![Sequential Search Use Sentinel
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Procedure SeqSearchBoolean (Input nama_array:tipe_array)
{I.S. : elemen array [1..maks_array] sudah terdefinisi}
{F.S. : menampilkan data yg dicari ditemukan atau tidak ditemukan}
Kamus:
i : integer
ketemu : boolean
data_cari : tipedata
Algoritma:
input(data_cari)
i 1
ketemu false
while (not ketemu) and (i ≤ maks_array) do
if(nama_var_array(i) = data_cari)
then
ketemu true
else
i i + 1
endif
endwhile
if (ketemu)
then
output(data_cari,’ ditemukan pada indeks ke-’,i)
else
output(data_cari,’ tidak ditemukan’)
endif
EndProcedure](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-16-320.jpg)
![Data that was sought: 7
Number
Result: ?
CaseExampleofBinarySearch
3 7 12 15 29
[1] [2] [3] [4] [5]](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-19-320.jpg)
![Case Example of Binary Search
Data that was sought: 7
Number
Result: ?
3 7 12 15 29
[1] [2] [3] [4] [5]](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-20-320.jpg)
![Case Example of Binary Search
Step 1 : Divide array into 2 parts. Count the middle
position (k) of array to start searching
k = (Ia + Ib) div 2
= (1 + 5) div 2
= 3
la : lower bound (for index)
lb : upper bound (for index)
3 7 12 15 29
[1] [2] [3] [4] [5]
Ia k Ib
Left Side Right Side](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-21-320.jpg)
![Case Example of Binary Search
Step 3 : repeat step 1 until step 2 until data is found or until
la>lb then stop searching.
Result : 7 is found in Number[2] and in the third looping.
3 7
1 2
Ia Ib
k
Left Side Right Side](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-23-320.jpg)
![Binary Search
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Procedure BinarySearch (Input nama_array : tipe_array)
{I.S. : elemen array yang terurut secara ascending sudah terdefinisi}
{F.S. : menampilkan data yg dicari ditemukan atau tidak ditemukan}
Kamus:
Ia, Ib, k : integer
ketemu : boolean
data_cari : tipedata
Algoritma:
input(data_cari)
Ia 1
Ib maks_array
ketemu false
while (not ketemu) and (Ia ≤ Ib) do
k (Ia + Ib) div 2
if (nama_var_array[k] = data_cari)
then
ketemu true
else
if (nama_var_array[k] < data_cari)
then
Ia k + 1
else
Ib k – 1
endif
endif
endwhile](https://image.slidesharecdn.com/chapter11-searching-161018112309/85/Algorithm-and-Programming-Searching-24-320.jpg)
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Algorithm and Programming (Searching)
- 1. Adam Mukharil Bachtiar English Class Informatics Engineering 2011 Algorithms and Programming Searching
- 2. Steps of the Day Let’s Start Definition of Searching Sequential Search Binary Search
- 3. Definition of Searching All About Searching
- 4. WhatisSearching Process that search the value in group of data. This process can produce FOUND or NOT FOUND value.
- 5. AlgorithmsofSorting • Sequential search / Linear search • Binary search
- 6. Sequential Search Definition and Structures of Sequential Search
- 7. WhatisSequentialSearch • Trace group of data one by one. • Start the process from the first data. • If the data was found in group then stop the searching but if not, search until the last data in grup.
- 8. MethodsinSequentialSearch • Without boolean Without sentinel Use sentinel • Use boolean
- 9. Ilustration of Seq. Search Without Sentinel Given an array to be processed: Number Data that want to be sought : 9 • Number[1] = 9? • Number[2] = 9? • Number[3] = 9? Result: 9 is found in number[3] 5 1 9 4 2 [1] [2] [3] [4] [5] i i + 1 i i + 1 i (STOP SEARCH)
- 10. Sequential Search Without Sentinel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Procedure SeqSearchTanpaSentinel (Input nama_array:tipe_array) {I.S. : elemen array [1..maks_array] sudah terdefinisi} {F.S. : menampilkan hasil pencarian (ditemukan/tidak)} Kamus: i : integer data_cari : tipedata Algoritma: input(data_cari) i 1 while(nama_array [i] ≠ data_cari) and (i < maks_array) do i i + 1 endwhile if (nama_array[i] = data_cari) then output(data_cari,’ ditemukan pada indeks ke-’,i) else output(data_cari,’ tidak ditemukan’) endif EndProcedure
- 11. SequentialSearchUseSentinel • Place the data that want to be sought in sentinel. • Sentinel is additional index that was placed in max array + 1. • If the data is found in sentinel that means the result is data is not found and vice versa.
- 12. Ilustration of Seq. Search Use Sentinel Data that was sought: 9 Number Result: Data was found in Number[3] Data that was sought: 10 Number Result: Data was not found 5 1 9 4 2 9 [1] [2] [3] [4] [5] [6] sentinel 5 1 9 4 2 10 [1] [2] [3] [4] [5] [6] sentinel
- 13. Sequential Search Use Sentinel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Procedure SeqSearchSentinel (Input nama_array:tipe_array) {I.S. : elemen array [1..maks_array] sudah terdefinisi} {F.S. : menampilkan hasil pencarian (ditemukan/tidak)} Kamus: i : integer data_cari : tipedata Algoritma: input(data_cari) i 1 nama_array(maks_array + 1) data_cari while (nama_array [i] ≠ data_cari) do i i + 1 endwhile if (i < maks_array+1) then output(data_cari,’ ditemukan pada indeks ke-’,i) else output(data_cari,’ tidak ditemukan’) endif EndProcedure
- 14. SequentialSearchUseBoolean • Its searching process is similar with another sequential search method. • Involves one boolean variable.
- 15. Ilustration of Seq. Search Use Boolean Given an array to be processed: Number Data that want to be sought : 9 • Number[1] = 9? • Number[2] = 9? • Number[3] = 9? Result: 9 is found in number[3] 5 1 9 4 2 [1] [2] [3] [4] [5] FOUND FALSE FOUND FALSE FOUND TRUE (STOP SEARCH)
- 16. Sequential Search Use Sentinel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Procedure SeqSearchBoolean (Input nama_array:tipe_array) {I.S. : elemen array [1..maks_array] sudah terdefinisi} {F.S. : menampilkan data yg dicari ditemukan atau tidak ditemukan} Kamus: i : integer ketemu : boolean data_cari : tipedata Algoritma: input(data_cari) i 1 ketemu false while (not ketemu) and (i ≤ maks_array) do if(nama_var_array(i) = data_cari) then ketemu true else i i + 1 endif endwhile if (ketemu) then output(data_cari,’ ditemukan pada indeks ke-’,i) else output(data_cari,’ tidak ditemukan’) endif EndProcedure
- 17. Binary Search Definition and Structures of Binary Search
- 18. WhatisBinarySearch • Searching algorithm that divide group of data into two parts (left and right). • First, check data in the middle. If same with the data that was sought then data is found. If not then continue searching process to left or right (based on condition). • Group of data must be sorted before the searching process.
- 19. Data that was sought: 7 Number Result: ? CaseExampleofBinarySearch 3 7 12 15 29 [1] [2] [3] [4] [5]
- 20. Case Example of Binary Search Data that was sought: 7 Number Result: ? 3 7 12 15 29 [1] [2] [3] [4] [5]
- 21. Case Example of Binary Search Step 1 : Divide array into 2 parts. Count the middle position (k) of array to start searching k = (Ia + Ib) div 2 = (1 + 5) div 2 = 3 la : lower bound (for index) lb : upper bound (for index) 3 7 12 15 29 [1] [2] [3] [4] [5] Ia k Ib Left Side Right Side
- 22. Case Example of Binary Search Step 2 : • check data in k. If it’s same with data that was sought then stop search and data is found. • If it’s not then check whether data was bigger or smaller than data in k. • If it’s bigger one then continue searching to right side and la = k+1. if it’s smaller one then continue searching to the left side and lb = k-1 (data wa sorted in ascending way). 3 7 1 2 Ia Ib
- 23. Case Example of Binary Search Step 3 : repeat step 1 until step 2 until data is found or until la>lb then stop searching. Result : 7 is found in Number[2] and in the third looping. 3 7 1 2 Ia Ib k Left Side Right Side
- 24. Binary Search 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Procedure BinarySearch (Input nama_array : tipe_array) {I.S. : elemen array yang terurut secara ascending sudah terdefinisi} {F.S. : menampilkan data yg dicari ditemukan atau tidak ditemukan} Kamus: Ia, Ib, k : integer ketemu : boolean data_cari : tipedata Algoritma: input(data_cari) Ia 1 Ib maks_array ketemu false while (not ketemu) and (Ia ≤ Ib) do k (Ia + Ib) div 2 if (nama_var_array[k] = data_cari) then ketemu true else if (nama_var_array[k] < data_cari) then Ia k + 1 else Ib k – 1 endif endif endwhile
- 25. Binary Search 27 28 29 30 31 32 33 if (ketemu) then output(data_cari,’ ditemukan pada indeks ke-’,k) else output(data_cari,’ tidak ditemukan’) endif EndProcedure
- 26. Contact Person: Adam Mukharil Bachtiar Informatics Engineering UNIKOM Jalan Dipati Ukur Nomor. 112-114 Bandung 40132 Email: [email protected] Blog: http://adfbipotter.wordpress.com Copyright © Adam Mukharil Bachtiar 2011