十大排序算法优化后-java实现=—带注释
package com.test.autimatic;
import java.util.Arrays;
/**
* @author 25338
* @version 1.0
* @date 2021/11/22 19:09
* @description
*/
public class Sort {
public static void main(String[] args) {
int[] arr = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr));
choiceSort(arr);
System.out.println(Arrays.toString(arr));
//插入
int[] arr1 = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr1));
insertSort(arr1);
System.out.println(Arrays.toString(arr1));
//希尔
int[] arr2 = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr2));
xiErSort(arr2);
System.out.println(Arrays.toString(arr2));
//快速
int[] arr3 = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr3));
quickSort(arr3,0,arr3.length-1);
System.out.println(Arrays.toString(arr3));
//归并
int[] arr4 = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr4));
mergeSort(arr4,0,arr4.length-1,new int[arr4.length]);
System.out.println(Arrays.toString(arr4));
//堆排序
int[] arr5 = {
21,3,4,2,1,22,21,26,7,8,6,7,51,5,23,33,35,36,87,88,0,4,5,6,6,5,5,7,7,7,980,1,9,19,0,88,66};
System.out.println(Arrays.toString(arr5));
heapSort(arr5);
System.out.println(Arrays.toString(arr5));
}
/**
* 選擇排序-找到数组中最小的数字
* @param arr
*/
public static void choiceSort(int[] arr){
for (int i = 0; i < arr.length; i++) {
int t = i;
//从签到后找到最小的数
for (int j = i + 1; j < arr.length; j++) {
if(arr[j]<arr[t]){
t = j;
}
}
if(i != t){
swap(arr,i,t);}//如果不想等则交换
}
}
/**
* 插入排序
* @param arr
*/
public static void insertSort(int[] arr){
for (int i = 1; i < arr.length; i++) {
//当不比前一个数小的时候停止
for (int j = i; j > 0 && arr[j] < arr[j-1]; j--) {
swap(arr,j,j-1);//否则交换两个数
}
}
}
/**
* 希尔排序
* @param arr
*/
public static void xiErSort(int[] arr){
//外层遍历负责分组排序
for (int i = arr.length/2; i > 0 ; i/=2) {
//第二层循环将数据按层排好序
for (int j = i; j < arr.length; j++) {
//第三层将数据比较按照i进行阶层排序
for (int k = j; k >= i && arr[k] < arr[k-i]; k-=i) {
swap(arr,k,k-i);
}
}
}
}
/**
* 三指针快速排序
* @param arr
* @param i
* @param j
*/
public static void quickSort(int[] arr,int i,int j){
//如果开始大于等于结束则停止
if(i >= j){
return;}
//定义一个比较的目标值--i为标准值，start为左侧开始节点，end为右侧开始节点,mid为标准值
int t = arr[i];int start = i + 1;int mid = i;int end = j;
while (start<=end){
//如果左侧值小于右侧继续
if(arr[start] < t){
//如果左侧值小于标准值，则交换，并且移动两个指针，标准值和左侧值指针
swap(arr,start++,mid++);
}else if(arr[start] > t){
//大于，则将此值交给右侧，并且移动右侧指针
swap(arr, start, end--);
}else{
//如果等于则移动左侧值
start++;
}
}
quickSort(arr, i, mid-1);//递归左侧部分
quickSort(arr, end+1, j);//递归右侧部分
}
/**
* 归并排序
* @param arr
* @param start
* @param end
* @param temp
*/
public static void mergeSort(int[] arr,int start,int end,int[] temp){
if(start >= end){
return; }//结束状态--开始值大于等于结束值
//归并排序--定义起始终止值
int mid = start + (end - start)/2;
//递归到最小值不能再分
mergeSort(arr,start,mid,temp);
mergeSort(arr,mid+1,end,temp);
//拷贝start - end段数组数据
int k = start;int i = start;int j = mid+1;
System.arraycopy(arr,i,temp,i,end-start+1);
while (k <= end){
if(i > mid){
//如果左侧数组达到最大值，则将右侧值不断赋值给arr
arr[k++] = temp[j++];
}else if(j > end){
//如果右侧数组达到最小值，则将左侧值不断赋值给arr
arr[k++] = temp[i++];
}else if(temp[i] > temp[j]){
//如果左侧数据比右测数据大则将有测数据赋值
arr[k++] = temp[j++];
}else{
//如果右侧数据比左测数据大则将有测数据赋值
arr[k++] = temp[i++];
}
}
}
/**
* 堆排序
* @param arr
*/
public static void heapSort(int[] arr){
//构建最大堆
for (int i = (arr.length/2)-1; i >= 0; i--) {
sink(arr,i,arr.length);
}
//交换并不断下沉
int n = arr.length - 1;
while (n >= 0){
//交换最大值
swap(arr,0,n--);
//下沉
sink(arr,0,n+1);
}
}
/**
* 下沉操作
* @param arr
* @param n
*/
private static void sink(int[] arr,int n,int len){
while ((n*2+1)<len){
int t = n * 2 + 1;//赋值子节点
if(t+1 < len && arr[t+1] > arr[t]){
t++;}//如果有右节点并且右侧节点比左侧节点大则将t赋值右节点下标
if(arr[n] >= arr[t]){
break;}//如果父节点比子节点大直接停止
swap(arr,n,t);//交换
n = t;//将子节点赋值为下一次下沉的指针
}
}
/**
* 数据交换
* @param arr
* @param a
* @param b
*/
private static void swap(int[] arr,int a,int b){
int t = arr[a];
arr[a] = arr[b];
arr[b] = t;
}
}