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增加 Java 实现 (#16)
* 增加 Java 实现 * 精简Java代码目录结构，去掉包名
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+1206
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lines changed

‎.gitignore

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@@ -15,3 +15,7 @@ _book
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*.mobi
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*.pdf
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\.idea/
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*.iml
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src/javaSortTest/target/

‎1.bubbleSort.md

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@@ -77,3 +77,36 @@ func bubbleSort(arr []int) []int {
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return arr
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}
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```
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## 8. Java 代码实现
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```java
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public class BubbleSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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for (int i = 1; i < arr.length; i++) {
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// 设定一个标记，若为true，则表示此次循环没有进行交换，也就是待排序列已经有序，排序已经完成。
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boolean flag = true;
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for (int j = 0; j < arr.length - i; j++) {
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if (arr[j] > arr[j + 1]) {
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int tmp = arr[j];
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arr[j] = arr[j + 1];
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arr[j + 1] = tmp;
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flag = false;
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}
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}
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if (flag) {
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break;
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}
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}
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return arr;
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}
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}
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```

‎10.radixSort.md

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@@ -47,4 +47,89 @@ function radixSort(arr, maxDigit) {
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}
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return arr;
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}
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```
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```
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## 4. Java 代码实现
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```java
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/**
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* 基数排序
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* 考虑负数的情况还可以参考： https://code.i-harness.com/zh-CN/q/e98fa9
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*/
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public class RadixSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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int maxDigit = getMaxDigit(arr);
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return radixSort(arr, maxDigit);
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}
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/**
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* 获取最高位数
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*/
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private int getMaxDigit(int[] arr) {
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int maxValue = getMaxValue(arr);
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return getNumLenght(maxValue);
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}
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private int getMaxValue(int[] arr) {
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int maxValue = arr[0];
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for (int value : arr) {
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if (maxValue < value) {
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maxValue = value;
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}
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}
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return maxValue;
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}
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protected int getNumLenght(long num) {
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if (num == 0) {
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return 1;
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}
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int lenght = 0;
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for (long temp = num; temp != 0; temp /= 10) {
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lenght++;
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}
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return lenght;
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}
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private int[] radixSort(int[] arr, int maxDigit) {
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int mod = 10;
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int dev = 1;
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for (int i = 0; i < maxDigit; i++, dev *= 10, mod *= 10) {
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// 考虑负数的情况，这里扩展一倍队列数，其中 [0-9]对应负数，[10-19]对应正数 (bucket + 10)
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int[][] counter = new int[mod * 2][0];
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for (int j = 0; j < arr.length; j++) {
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int bucket = ((arr[j] % mod) / dev) + mod;
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counter[bucket] = arrayAppend(counter[bucket], arr[j]);
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}
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int pos = 0;
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for (int[] bucket : counter) {
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for (int value : bucket) {
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arr[pos++] = value;
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}
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}
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}
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return arr;
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}
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/**
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* 自动扩容，并保存数据
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*
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* @param arr
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* @param value
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*/
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private int[] arrayAppend(int[] arr, int value) {
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arr = Arrays.copyOf(arr, arr.length + 1);
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arr[arr.length - 1] = value;
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return arr;
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}
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}
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```

‎2.selectionSort.md

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@@ -71,3 +71,37 @@ func selectionSort(arr []int) []int {
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return arr
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}
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```
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## 6. Java 代码实现
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```java
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public class SelectionSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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// 总共要经过 N-1 轮比较
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for (int i = 0; i < arr.length - 1; i++) {
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int min = i;
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// 每轮需要比较的次数 N-i
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for (int j = i + 1; j < arr.length; j++) {
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if (arr[j] < arr[min]) {
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// 记录目前能找到的最小值元素的下标
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min = j;
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}
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}
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// 将找到的最小值和i位置所在的值进行交换
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if (i != min) {
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int tmp = arr[i];
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arr[i] = arr[min];
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arr[min] = tmp;
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}
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}
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return arr;
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}
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}
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```

‎3.insertionSort.md

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@@ -65,3 +65,37 @@ func insertionSort(arr []int) []int {
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return arr
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}
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```
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## 6. Java 代码实现
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```java
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public class InsertSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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// 从下标为1的元素开始选择合适的位置插入，因为下标为0的只有一个元素，默认是有序的
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for (int i = 1; i < arr.length; i++) {
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// 记录要插入的数据
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int tmp = arr[i];
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// 从已经排序的序列最右边的开始比较，找到比其小的数
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int j = i;
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while (j > 0 && tmp < arr[j - 1]) {
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arr[j] = arr[j - 1];
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j--;
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}
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// 存在比其小的数，插入
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if (j != i) {
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arr[j] = tmp;
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}
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}
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return arr;
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}
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}
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```

‎4.shellSort.md

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@@ -87,3 +87,36 @@ func shellSort(arr []int) []int {
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return arr
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}
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```
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## 5. Java 代码实现
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```java
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public class ShellSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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int gap = 1;
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while (gap < arr.length) {
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gap = gap * 3 + 1;
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}
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while (gap > 0) {
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for (int i = gap; i < arr.length; i++) {
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int tmp = arr[i];
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int j = i - gap;
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while (j >= 0 && arr[j] > tmp) {
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arr[j + gap] = arr[j];
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j -= gap;
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}
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arr[j + gap] = tmp;
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}
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gap = (int) Math.floor(gap / 3);
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}
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return arr;
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}
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}
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```

‎5.mergeSort.md

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@@ -136,3 +136,53 @@ func merge(left []int, right []int) []int {
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return result
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}
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```
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## 7. Java 代码实现
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```java
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public class MergeSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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if (arr.length < 2) {
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return arr;
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}
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int middle = (int) Math.floor(arr.length / 2);
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int[] left = Arrays.copyOfRange(arr, 0, middle);
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int[] right = Arrays.copyOfRange(arr, middle, arr.length);
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return merge(sort(left), sort(right));
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}
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protected int[] merge(int[] left, int[] right) {
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int[] result = new int[left.length + right.length];
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int i = 0;
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while (left.length > 0 && right.length > 0) {
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if (left[0] <= right[0]) {
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result[i++] = left[0];
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left = Arrays.copyOfRange(left, 1, left.length);
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} else {
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result[i++] = right[0];
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right = Arrays.copyOfRange(right, 1, right.length);
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}
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}
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while (left.length > 0) {
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result[i++] = left[0];
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left = Arrays.copyOfRange(left, 1, left.length);
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}
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while (right.length > 0) {
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result[i++] = right[0];
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right = Arrays.copyOfRange(right, 1, right.length);
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}
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return result;
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}
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}
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```

‎6.quickSort.md

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void QuickSort(int A[], int low, int high) //快排母函数
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{
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if (low < high) {
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int pivot = Paritition1(A, low, high);
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int pivot = Paritition1(A, low, high);
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QuickSort(A, low, pivot - 1);
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QuickSort(A, pivot + 1, high);
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}
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}
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```
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## 7. Java 代码实现
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```java
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public class QuickSort implements IArraySort {
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@Override
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public int[] sort(int[] sourceArray) throws Exception {
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// 对 arr 进行拷贝，不改变参数内容
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int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
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return quickSort(arr, 0, arr.length - 1);
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}
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private int[] quickSort(int[] arr, int left, int right) {
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if (left < right) {
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int partitionIndex = partition(arr, left, right);
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quickSort(arr, left, partitionIndex - 1);
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quickSort(arr, partitionIndex + 1, right);
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}
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return arr;
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}
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private int partition(int[] arr, int left, int right) {
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// 设定基准值（pivot）
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int pivot = left;
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int index = pivot + 1;
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for (int i = index; i <= right; i++) {
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if (arr[i] < arr[pivot]) {
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swap(arr, i, index);
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index++;
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}
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}
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swap(arr, pivot, index - 1);
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return index - 1;
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}
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private void swap(int[] arr, int i, int j) {
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int temp = arr[i];
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arr[i] = arr[j];
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arr[j] = temp;
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}
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}
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```

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