diff --git a/.gitignore b/.gitignore
index f6cbc5f..28fee88 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,14 @@ _book
*.pdf
\.idea/
+# idea
*.iml
-src/javaSortTest/target/
+# elipse
+.classpath
+.project
+.settings
+
+# build
+target
+bin
\ No newline at end of file
diff --git a/5.mergeSort.md b/5.mergeSort.md
index bf0de32..2379ad6 100644
--- a/5.mergeSort.md
+++ b/5.mergeSort.md
@@ -143,47 +143,52 @@ func merge(left []int, right []int) []int {
public class MergeSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
+ public int[] sort(int[] arr) throws Exception {
+ mergeSort(arr, 0, arr.length - 1);
+ return arr;
+ }
- if (arr.length < 2) {
- return arr;
+ private void mergeSort(int[] arr, int left, int right) {
+ if (left >= right) {
+ return;
}
- int middle = (int) Math.floor(arr.length / 2);
- int[] left = Arrays.copyOfRange(arr, 0, middle);
- int[] right = Arrays.copyOfRange(arr, middle, arr.length);
+ int mid = (right + left) / 2;
- return merge(sort(left), sort(right));
+ //分
+ mergeSort(arr, left, mid);
+ mergeSort(arr, mid + 1, right);
+ //治
+ merge(arr, left, mid, right);
}
- protected int[] merge(int[] left, int[] right) {
- int[] result = new int[left.length + right.length];
- int i = 0;
- while (left.length > 0 && right.length > 0) {
- if (left[0] <= right[0]) {
- result[i++] = left[0];
- left = Arrays.copyOfRange(left, 1, left.length);
+
+ /**
+ * 主要思想， 两个已经排序好的数组， 如何归并
+ * 当元素个数趋近单个元素时， 归并即为排序过程
+ */
+ private void merge(int[] arr, int left, int mid, int right) {
+ int[] tmp = new int[right - left + 1];
+
+ int i = left;
+ int j = mid + 1;
+ int k = 0;
+
+ while (i <= mid && j <= right) {
+ if (arr[i] <= arr[j]) { //取等号， 优先匹配左边数组予以填充
+ tmp[k++] = arr[i++];
} else {
- result[i++] = right[0];
- right = Arrays.copyOfRange(right, 1, right.length);
+ tmp[k++] = arr[j++];
}
}
- while (left.length > 0) {
- result[i++] = left[0];
- left = Arrays.copyOfRange(left, 1, left.length);
- }
-
- while (right.length > 0) {
- result[i++] = right[0];
- right = Arrays.copyOfRange(right, 1, right.length);
- }
+ //队尾的直接填充
+ while (i <= mid) tmp[k++] = arr[i++];
+ while (j <= right) tmp[k++] = arr[j++];
- return result;
+ //覆盖原数组
+ System.arraycopy(tmp, 0, arr, left, tmp.length);
}
-
}
```
diff --git a/src/java/main/BubbleSort.java b/src/java/main/BubbleSort.java
index 3c8cebc..9e99ee4 100644
--- a/src/java/main/BubbleSort.java
+++ b/src/java/main/BubbleSort.java
@@ -6,10 +6,7 @@
public class BubbleSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
for (int i = 1; i < arr.length; i++) {
// 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。
boolean flag = true;
diff --git a/src/java/main/BucketSort.java b/src/java/main/BucketSort.java
index c0b5183..2d80c29 100644
--- a/src/java/main/BucketSort.java
+++ b/src/java/main/BucketSort.java
@@ -8,10 +8,7 @@ public class BucketSort implements IArraySort {
private static final InsertSort insertSort = new InsertSort();
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
return bucketSort(arr, 5);
}
diff --git a/src/java/main/CountingSort.java b/src/java/main/CountingSort.java
index 74fcd2a..cfbce9f 100644
--- a/src/java/main/CountingSort.java
+++ b/src/java/main/CountingSort.java
@@ -6,10 +6,7 @@
public class CountingSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
int maxValue = getMaxValue(arr);
return countingSort(arr, maxValue);
diff --git a/src/java/main/HeapSort.java b/src/java/main/HeapSort.java
index 6e9dcfe..6b5ca3f 100644
--- a/src/java/main/HeapSort.java
+++ b/src/java/main/HeapSort.java
@@ -6,10 +6,7 @@
public class HeapSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
int len = arr.length;
buildMaxHeap(arr, len);
diff --git a/src/java/main/InsertSort.java b/src/java/main/InsertSort.java
index 1321972..6eac37a 100644
--- a/src/java/main/InsertSort.java
+++ b/src/java/main/InsertSort.java
@@ -6,10 +6,7 @@
public class InsertSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
// 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
for (int i = 1; i < arr.length; i++) {
diff --git a/src/java/main/MergeSort.java b/src/java/main/MergeSort.java
index 6457036..bed6cf0 100644
--- a/src/java/main/MergeSort.java
+++ b/src/java/main/MergeSort.java
@@ -1,50 +1,55 @@
-import java.util.Arrays;
-
/**
* 归并排序
+ * @author qrqhuangcy
+ * @date 2020/5/4
*/
public class MergeSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
+ public int[] sort(int[] arr) throws Exception {
+ mergeSort(arr, 0, arr.length - 1);
+ return arr;
+ }
- if (arr.length < 2) {
- return arr;
+ private void mergeSort(int[] arr, int left, int right) {
+ if (left >= right) {
+ return;
}
- int middle = (int) Math.floor(arr.length / 2);
- int[] left = Arrays.copyOfRange(arr, 0, middle);
- int[] right = Arrays.copyOfRange(arr, middle, arr.length);
+ int mid = (right + left) / 2;
- return merge(sort(left), sort(right));
+ //分
+ mergeSort(arr, left, mid);
+ mergeSort(arr, mid + 1, right);
+ //治
+ merge(arr, left, mid, right);
}
- protected int[] merge(int[] left, int[] right) {
- int[] result = new int[left.length + right.length];
- int l = 0, r = 0, len = 0;
- while (len < left.length + right.length) {
- if (left[l] <= right[r]) {
- result[len++] = left[l++];
-
- if (l == left.length) {
- for (int i = r; i < right.length; i++) {
- result[len++] = right[r++];
- }
- }
- } else {
- result[len++] = right[r++];
- if (r == right.length) {
- for (int i = l; i < left.length; i++) {
- result[len++] = left[l++];
- }
- }
+ /**
+ * 主要思想， 两个已经排序好的数组， 如何归并
+ * 当元素个数趋近单个元素时， 归并即为排序过程
+ */
+ private void merge(int[] arr, int left, int mid, int right) {
+ int[] tmp = new int[right - left + 1];
+
+ int i = left;
+ int j = mid + 1;
+ int k = 0;
+
+ while (i <= mid && j <= right) {
+ if (arr[i] <= arr[j]) { //取等号， 优先匹配左边数组予以填充
+ tmp[k++] = arr[i++];
+ } else {
+ tmp[k++] = arr[j++];
}
}
- return result;
- }
+ //队尾的直接填充
+ while (i <= mid) tmp[k++] = arr[i++];
+ while (j <= right) tmp[k++] = arr[j++];
+ //覆盖原数组
+ System.arraycopy(tmp, 0, arr, left, tmp.length);
+ }
}
diff --git a/src/java/main/QuickSort.java b/src/java/main/QuickSort.java
index 1c598ed..838827b 100644
--- a/src/java/main/QuickSort.java
+++ b/src/java/main/QuickSort.java
@@ -6,10 +6,7 @@
public class QuickSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
return quickSort(arr, 0, arr.length - 1);
}
diff --git a/src/java/main/RadixSort.java b/src/java/main/RadixSort.java
index 9052e76..3c9adaa 100644
--- a/src/java/main/RadixSort.java
+++ b/src/java/main/RadixSort.java
@@ -8,10 +8,7 @@
public class RadixSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
int maxDigit = getMaxDigit(arr);
return radixSort(arr, maxDigit);
}
diff --git a/src/java/main/SelectionSort.java b/src/java/main/SelectionSort.java
index 0cee685..7c188b3 100644
--- a/src/java/main/SelectionSort.java
+++ b/src/java/main/SelectionSort.java
@@ -6,9 +6,7 @@
public class SelectionSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
// 总共要经过 N-1 轮比较
for (int i = 0; i < arr.length - 1; i++) {
int min = i;
diff --git a/src/java/main/ShellSort.java b/src/java/main/ShellSort.java
index 6c0fbb1..fbb5cae 100644
--- a/src/java/main/ShellSort.java
+++ b/src/java/main/ShellSort.java
@@ -1,15 +1,10 @@
-import java.util.Arrays;
-
/**
* 希尔排序
*/
public class ShellSort implements IArraySort {
@Override
- public int[] sort(int[] sourceArray) throws Exception {
- // 对 arr 进行拷贝，不改变参数内容
- int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
-
+ public int[] sort(int[] arr) throws Exception {
int gap = 1;
while (gap < arr.length) {
gap = gap * 3 + 1;
diff --git a/src/java/pom.xml b/src/java/pom.xml
index 60b4858..70e5dc6 100644
--- a/src/java/pom.xml
+++ b/src/java/pom.xml
@@ -33,6 +33,9 @@
</dependencies>
<build>
+ <sourceDirectory>main</sourceDirectory>
+ <testSourceDirectory>test</testSourceDirectory>
+
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
diff --git a/src/java/target/maven-archiver/pom.properties b/src/java/target/maven-archiver/pom.properties
deleted file mode 100644
index 5239a24..0000000
--- a/src/java/target/maven-archiver/pom.properties
+++ /dev/null
@@ -1,5 +0,0 @@
-#Generated by Maven
-#Fri Jan 05 09:51:14 CST 2018
-version=1.0-SNAPSHOT
-groupId=com.corning
-artifactId=sort
diff --git a/src/java/target/sort-1.0-SNAPSHOT.jar b/src/java/target/sort-1.0-SNAPSHOT.jar
deleted file mode 100644
index 14116be..0000000
Binary files a/src/java/target/sort-1.0-SNAPSHOT.jar and /dev/null differ
diff --git a/src/java/test/ArraySortTest.java b/src/java/test/ArraySortTest.java
index 580701f..9fd348a 100644
--- a/src/java/test/ArraySortTest.java
+++ b/src/java/test/ArraySortTest.java
@@ -101,13 +101,6 @@ 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));