Java Reference
In-Depth Information
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// Fig. 19.4: SelectionSortTest.java
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// Sorting an array with selection sort.
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import
java.security.SecureRandom;
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import
java.util.Arrays;
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public class
SelectionSortTest
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{
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// sort array using selection sort
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public static void
selectionSort(
int
[] data)
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{
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// loop over data.length - 1 elements
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for
(
int
i =
0
; i < data.length -
1
; i++)
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{
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int
smallest = i;
// first index of remaining array
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// loop to find index of smallest element
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for
(
int
index = i +
1
; index < data.length; index++)
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if
(data[index] < data[smallest])
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smallest = index;
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swap(data, i, smallest);
// swap smallest element into position
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printPass(i +
1
, smallest);
// output pass of algorithm
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}
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}
// end method selectionSort
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// helper method to swap values in two elements
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private static void
swap(
int
[] data,
int
first,
int
second)
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{
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int
temporary = data[first];
// store first in temporary
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data[first] = data[second];
// replace first with second
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data[second] = temporary;
// put temporary in second
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}
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// print a pass of the algorithm
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private static void
printPass(
int
[] data,
int
pass,
int
index)
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{
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System.out.printf(
"after pass %2d: "
, pass);
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// output elements till selected item
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for
(
int
i =
0
; i < index; i++)
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System.out.printf(
"%d "
, data[i]);
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System.out.printf(
"%d* "
, data[index]);
// indicate swap
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// finish outputting array
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for
(
int
i = index +
1
; i < data.length; i++)
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System.out.printf(
"%d "
, data[i]);
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System.out.printf(
"%n "
);
// for alignment
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// indicate amount of array that's sorted
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for
(
int
j =
0
; j < pass; j++)
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System.out.print(
"-- "
);
Fig. 19.4
|
Sorting an array with selection sort. (Part 1 of 2.)
