import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import java.util.Arrays;
import java.util.Random;
import static org.junit.Assert.*;
/**
* Created by corning on 2017/12/19.
*/
public class ArraySortTest {
private int[] array;
private int[] sortedArray;
// 计数排序等不支持负数排序
private int[] positiveArray;
private int[] positiveArraySorted;
@Before
public void setUp() throws Exception {
// 生成随机数组
array = randomArray(-1000, 1000, 100);
// 使用 Arrays.sort() 排序作为对比
sortedArray = Arrays.copyOf(array, array.length);
Arrays.sort(sortedArray);
positiveArray = randomArray(0, 1000, 100);
positiveArraySorted = Arrays.copyOf(positiveArray, positiveArray.length);
Arrays.sort(positiveArraySorted);
}
/**
* 随机指定范围内N个不重复的数
* 在初始化的无重复待选数组中随机产生一个数放入结果中，
* 将待选数组被随机到的数，用待选数组(len-1)下标对应的数替换
* 然后从len-2里随机产生下一个随机数，如此类推
*
* @param max 指定范围最大值
* @param min 指定范围最小值
* @param n 随机数个数
* @return int[] 随机数结果集
*/
public int[] randomArray(int min, int max, int n) {
int len = max - min + 1;
if (max < min || n > len) {
return null;
}
//初始化给定范围的待选数组
int[] source = new int[len];
for (int i = min; i < min + len; i++) {
source[i - min] = i;
}
int[] result = new int[n];
Random rd = new Random();
int index = 0;
for (int i = 0; i < result.length; i++) {
//待选数组0到(len-2)随机一个下标
index = Math.abs(rd.nextInt() % len--);
//将随机到的数放入结果集
result[i] = source[index];
//将待选数组中被随机到的数，用待选数组(len-1)下标对应的数替换
source[index] = source[len];
}
return result;
}
@After
public void tearDown() throws Exception {
array = null;
sortedArray = null;
}
@Test
public void bubbleSort() throws Exception {
assertArrayEquals(sortedArray, new BubbleSort().sort(array));
}
@Test
public void choiceSort() throws Exception {
assertArrayEquals(sortedArray, new SelectionSort().sort(array));
}
@Test
public void insertSort() throws Exception {
assertArrayEquals(sortedArray, new InsertSort().sort(array));
}
@Test
public void shellSort() throws Exception {
assertArrayEquals(sortedArray, new ShellSort().sort(array));
}
@Test
public void mergeSort() throws Exception {
assertArrayEquals(sortedArray, new MergeSort().sort(array));
}
@Test
public void mergeSort_merge() throws Exception {
assertArrayEquals(new int[]{1, 2}, new MergeSort().merge(new int[]{1, 2}, new int[]{}));
assertArrayEquals(new int[]{1, 2}, new MergeSort().merge(new int[]{1}, new int[]{2}));
assertArrayEquals(new int[]{1, 2, 3}, new MergeSort().merge(new int[]{1, 3}, new int[]{2}));
}
@Test
public void quickSort() throws Exception {
assertArrayEquals(sortedArray, new QuickSort().sort(array));
}
@Test
public void heapSort() throws Exception {
assertArrayEquals(sortedArray, new HeapSort().sort(array));
}
@Test
public void countingSort() throws Exception {
assertArrayEquals(positiveArraySorted, new CountingSort().sort(positiveArray));
}
@Test
public void bucketSort() throws Exception {
assertArrayEquals(sortedArray, new BucketSort().sort(array));
}
@Test
public void radixSort() throws Exception {
assertArrayEquals(sortedArray, new RadixSort().sort(array));
}
@Test
public void radixSort_getNumLenght() throws Exception {
assertEquals(3, new RadixSort().getNumLenght(-100));
assertEquals(1, new RadixSort().getNumLenght(1));
}
}