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Selection Sort Implementation (#7454)

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* Selection sort implementation

* Selection sort implementation
This commit is contained in:
nikunjgandhi1987 2019-08-07 21:59:06 -04:00 committed by Josh Cummings
parent f90828bfc0
commit 71db72a68a
2 changed files with 63 additions and 0 deletions
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38
algorithms-sorting/src/main/java/com/baeldung/algorithms/selectionsort/SelectionSort.java Normal file
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package com.baeldung.algorithms.selectionsort;
public class SelectionSort {
public static void sortAscending(final int[] arr) {
for (int i = 0; i < arr.length - 1; i++) {
int minElementIndex = i;
for (int j = i + 1; j < arr.length; j++) {
if (arr[minElementIndex] > arr[j]) {
minElementIndex = j;
}
}
if (minElementIndex != i) {
int temp = arr[i];
arr[i] = arr[minElementIndex];
arr[minElementIndex] = temp;
}
}
}
public static void sortDescending(final int[] arr) {
for (int i = 0; i < arr.length - 1; i++) {
int maxElementIndex = i;
for (int j = i + 1; j < arr.length; j++) {
if (arr[maxElementIndex] < arr[j]) {
maxElementIndex = j;
}
}
if (maxElementIndex != i) {
int temp = arr[i];
arr[i] = arr[maxElementIndex];
arr[maxElementIndex] = temp;
}
}
}
}

25
algorithms-sorting/src/test/java/com/baeldung/algorithms/selectionsort/SelectionSortUnitTest.java Normal file
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package com.baeldung.algorithms.selectionsort;
import static org.junit.Assert.*;
import static org.junit.Assert.assertArrayEquals;
import org.junit.Test;
public class SelectionSortUnitTest {
@Test
public void givenUnsortedArray_whenSelectionSort_SortAscending_thenSortedAsc() {
int[] input = { 5, 4, 1, 6, 2 };
SelectionSort.sortAscending(input);
int[] expected = {1, 2, 4, 5, 6};
assertArrayEquals("the two arrays are not equal", expected, input);
}
@Test
public void givenUnsortedArray_whenSelectionSort_SortDescending_thenSortedDesc() {
int[] input = { 5, 4, 1, 6, 2 };
SelectionSort.sortDescending(input);
int[] expected = {6, 5, 4, 2, 1};
assertArrayEquals("the two arrays are not equal", expected, input);
}
}