常见的排序方法以及java实现代码
时间: 2023-09-12 13:05:34 浏览: 68
### 回答1:
常见的排序方法包括:冒泡排序、快速排序、插入排序、选择排序、堆排序、希尔排序等。Java实现代码可以参考:http://www.cnblogs.com/java-my-life/archive/2012/05/16/2502240.html 。
### 回答2:
常见的排序方法有冒泡排序、选择排序、插入排序、希尔排序、归并排序、快速排序和堆排序。以下是这些排序方法的Java实现代码。
1. 冒泡排序:
```java
public static void bubbleSort(int[] arr) {
int n = arr.length;
for (int i = 0; i < n-1; i++) {
for (int j = 0; j < n-i-1; j++) {
if (arr[j] > arr[j+1]) {
// 交换arr[j]和arr[j+1]
int temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
}
```
2. 选择排序:
```java
public static void selectionSort(int[] arr) {
int n = arr.length;
for (int i = 0; i < n-1; i++) {
int minIndex = i;
for (int j = i+1; j < n; j++) {
if (arr[j] < arr[minIndex]) {
minIndex = j;
}
}
// 交换arr[i]和arr[minIndex]
int temp = arr[i];
arr[i] = arr[minIndex];
arr[minIndex] = temp;
}
}
```
3. 插入排序:
```java
public static void insertionSort(int[] arr) {
int n = arr.length;
for (int i = 1; i < n; i++) {
int key = arr[i];
int j = i - 1;
while (j >= 0 && arr[j] > key) {
arr[j+1] = arr[j];
j--;
}
arr[j+1] = key;
}
}
```
4. 希尔排序:
```java
public static void shellSort(int[] arr) {
int n = arr.length;
for (int gap = n/2; gap > 0; gap /= 2) {
for (int i = gap; i < n; i++) {
int key = arr[i];
int j = i;
while (j >= gap && arr[j-gap] > key) {
arr[j] = arr[j - gap];
j -= gap;
}
arr[j] = key;
}
}
}
```
5. 归并排序:
```java
public static void mergeSort(int[] arr, int left, int right) {
if (left < right) {
int mid = (left + right) / 2;
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
}
public static void merge(int[] arr, int left, int mid, int right) {
int n1 = mid - left + 1;
int n2 = right - mid;
int[] L = new int[n1];
int[] R = new int[n2];
for (int i = 0; i < n1; ++i) {
L[i] = arr[left + i];
}
for (int j = 0; j < n2; ++j) {
R[j] = arr[mid + 1 + j];
}
int i = 0, j = 0;
int k = left;
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
} else {
arr[k] = R[j];
j++;
}
k++;
}
while (i < n1) {
arr[k] = L[i];
i++;
k++;
}
while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
}
```
6. 快速排序:
```java
public static void quickSort(int[] arr, int low, int high) {
if (low < high) {
int pi = partition(arr, low, high);
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
}
}
public static int partition(int[] arr, int low, int high) {
int pivot = arr[high];
int i = low - 1;
for (int j = low; j < high; j++) {
if (arr[j] < pivot) {
i++;
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
int temp = arr[i+1];
arr[i+1] = arr[high];
arr[high] = temp;
return i+1;
}
```
7. 堆排序:
```java
public static void heapSort(int[] arr) {
int n = arr.length;
for (int i = n / 2 - 1; i >= 0; i--) {
heapify(arr, n, i);
}
for (int i = n - 1; i > 0; i--) {
int temp = arr[0];
arr[0] = arr[i];
arr[i] = temp;
heapify(arr, i, 0);
}
}
public static void heapify(int[] arr, int n, int i) {
int largest = i;
int left = 2 * i + 1;
int right = 2 * i + 2;
if (left < n && arr[left] > arr[largest]) {
largest = left;
}
if (right < n && arr[right] > arr[largest]) {
largest = right;
}
if (largest != i) {
int temp = arr[i];
arr[i] = arr[largest];
arr[largest] = temp;
heapify(arr, n, largest);
}
}
```
### 回答3:
常见的排序方法有冒泡排序、选择排序、插入排序、快速排序和归并排序等。
1. 冒泡排序:
冒泡排序是一种比较简单的排序方法,通过相邻元素的比较和交换来实现排序。具体代码实现如下:
```java
public static void bubbleSort(int[] arr) {
int len = arr.length;
for (int i = 0; i < len - 1; i++) {
for (int j = 0; j < len - 1 - i; j++) {
if (arr[j] > arr[j + 1]) {
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
```
2. 选择排序:
选择排序是每次遍历找到未排序部分的最小元素,并将其放到已排序部分的末尾。具体代码实现如下:
```java
public static void selectionSort(int[] arr) {
int len = arr.length;
for (int i = 0; i < len - 1; i++) {
int minIndex = i;
for (int j = i + 1; j < len; j++) {
if (arr[j] < arr[minIndex]) {
minIndex = j;
}
}
if (minIndex != i) {
int temp = arr[i];
arr[i] = arr[minIndex];
arr[minIndex] = temp;
}
}
}
```
3. 插入排序:
插入排序将未排序部分的第一个元素插入到已排序部分的合适位置。具体代码实现如下:
```java
public static void insertionSort(int[] arr) {
int len = arr.length;
for (int i = 1; i < len; i++) {
int j = i;
int current = arr[i];
while (j > 0 && arr[j - 1] > current) {
arr[j] = arr[j - 1];
j--;
}
arr[j] = current;
}
}
```
4. 快速排序:
快速排序是一种分治思想的排序算法,通过选取一个基准元素,将数组划分为左右两个子数组,对子数组进行递归排序。具体代码实现如下:
```java
public static void quickSort(int[] arr, int low, int high) {
if (low < high) {
int partitionIndex = partition(arr, low, high);
quickSort(arr, low, partitionIndex - 1);
quickSort(arr, partitionIndex + 1, high);
}
}
public static int partition(int[] arr, int low, int high) {
int pivot = arr[high];
int i = low - 1;
for (int j = low; j < high; j++) {
if (arr[j] < pivot) {
i++;
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
int temp = arr[i + 1];
arr[i + 1] = arr[high];
arr[high] = temp;
return i + 1;
}
```
5. 归并排序:
归并排序是一种将数组拆分为若干个子数组,并对每个子数组进行排序,然后再合并的排序算法。具体代码实现如下:
```java
public static void mergeSort(int[] arr, int left, int right) {
if (left < right) {
int mid = (left + right) / 2;
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
}
public static void merge(int[] arr, int left, int mid, int right) {
int[] temp = 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]) {
temp[k] = arr[i];
i++;
} else {
temp[k] = arr[j];
j++;
}
k++;
}
while (i <= mid) {
temp[k] = arr[i];
i++;
k++;
}
while (j <= right) {
temp[k] = arr[j];
j++;
k++;
}
for (int m = 0; m < temp.length; m++) {
arr[left + m] = temp[m];
}
}
```
以上是常见排序方法的Java实现代码。每种排序方法都有其特点和优劣,根据具体场景可以选择合适的排序方法。