1、选择排序
import java.util.Scanner ;
public class Selection{ //选择排序
public static void selectionSort(Comparable[] a){
int n = a.length ;
for (int i=0;i<n-1;i++) {
int min = i ;
for (int j=i+1;j<n;j++) {
if (less(a[j],a[min])) {
min = j ;
}
}
exch(a,i,min) ;
}
}
private static boolean less(Comparable v, Comparable w){ //判断大小
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素 ；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印出来
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){//测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
selectionSort(a) ;
}
show(a) ;
}
}
2、冒泡排序
import java.util.Scanner ;
public class Bubble{ //冒泡排序；
public static void bubbleSort(Comparable[] a){
int n = a.length ;
for (int i=1;i<n;i++) {
for (int j=0;j<n-i;j++) {
if (less(a[j+1],a[j])) {
exch(a,j,j+1) ;
}
}
}
}
private static boolean less(Comparable v, Comparable w){ //判断元素大小；
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印；
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){//测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
bubbleSort(a) ;
}
show(a) ;
}
}
3、插入排序
import java.util.Scanner ;
public class Insertion{ //插入排序；
public static void insertionSort(Comparable[] a){ //方法一；
int n = a.length ;
for (int i=1;i<n;i++) {
for (int j=i;j>0 && less(a[j],a[j-1]);j--) {
exch(a,j,j-1) ;
}
}
}
public static void insertionSort02(Comparable[] a){ //方法二；
int n = a.length ;
for (int i=1;i<n;i++) {
Comparable temp = a[i] ;
int j = i ;
for (j=i-1;j>=0 && less(temp,a[j]);j--) {
a[j+1] = a[j] ;
}
a[j+1] = temp ;
}
}
private static boolean less(Comparable v, Comparable w){ //判断元素大小；
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印；
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){//测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
insertionSort02(a) ;
}
show(a) ;
}
}
4、希尔排序
import java.util.Scanner ;
public class Shell{ //希尔排序；
public static void shellSort(Comparable[] a){
int n = a.length ;
int h = 1 ;
while(h<n/3){
h = 3*h + 1 ;
}
while(h>=1){
for (int i=h;i<n;i++) {
for (int j=i;j>=h && less(a[j],a[j-h]);j=j-h) {
exch(a,j,j-h) ;
}
}
h = h/3 ;
}
}
private static boolean less(Comparable v, Comparable w){ //判断元素大小；
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印；
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){ //测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
shellSort(a) ;
}
show(a) ;
}
}
5、归并排序
import java.util.Scanner ;
public class Merge{//归并排序；
private static Comparable[] aux ;
public static void mergeSort(Comparable[] a){
aux = new Comparable[a.length] ;
mergeSort(a,0,a.length-1) ;
}
private static void mergeSort(Comparable[] a, int lo, int hi){
if (lo<hi) {
int mid = (lo+hi)/2 ;
mergeSort(a,lo,mid) ;
mergeSort(a,mid+1,hi) ;
merge(a,lo,mid,hi) ;
}else{
return ;
}
}
private static void merge(Comparable[] a, int lo, int mid, int hi){
int i = lo ;
int j = mid+1 ;
for (int k=lo;k<=hi;k++) {
aux[k] = a[k] ;
}
for (int k=lo;k<=hi;k++) {
if (i>mid) {
a[k] = aux[j] ;
j++ ;
}else if(j>hi){
a[k] = aux[i] ;
i++ ;
}else if(less(aux[i],aux[j])){
a[k] = aux[i] ;
i++ ;
}else{
a[k] = aux[j] ;
j++ ;
}
}
}
private static boolean less(Comparable v, Comparable w){ //判断元素大小；
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印；
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){//测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
mergeSort(a) ;
}
show(a) ;
}
}
6、快速排序
import java.util.Scanner ;
public class Quick{ //快速排序；
public static void quickSort(Comparable[] a){
quickSort(a,0,a.length-1) ;
}
private static void quickSort(Comparable[] a, int lo, int hi){
if (lo<hi) {
int j = partition(a,lo,hi) ;
quickSort(a,lo,j-1) ;
quickSort(a,j+1,hi) ;
}else{
return ;
}
}
private static int partition(Comparable[] a, int lo, int hi){
int i = lo ;
int j = hi ;
Comparable temp = a[lo] ;
while(i!=j){
while(i<j && !less(a[j],temp)){
j-- ;
}
while(i<j && !less(temp,a[i])){
i++ ;
}
if (i!=j) {
exch(a,i,j) ;
}
}
exch(a,lo,i) ;
return j ;
}
private static boolean less(Comparable v, Comparable w){ //判断元素大小；
if (v.compareTo(w)<0) {
return true ;
}else{
return false ;
}
}
private static void exch(Comparable[] a, int i, int j){ //交换元素；
Comparable temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
private static void show(Comparable[] a){ //打印；
for (int i=0;i<a.length;i++) {
System.out.print(a[i] + " ") ;
}
System.out.println() ;
}
public static boolean isSorted(Comparable[] a){ //判断是否已排序；
for(int i=1;i<a.length;i++){
if (less(a[i],a[i-1])) {
return false ;
}
}
return true ;
}
public static void main(String[] args){//测试；
System.out.println("please input the length of array:") ;
Scanner sc = new Scanner(System.in) ;
int len = sc.nextInt() ;
String[] a = new String[len] ;
System.out.println("please input the numbers of array:") ;
for (int i=0;i<len;i++) {
a[i] = sc.next() ;
}
if (!isSorted(a)) {
quickSort(a) ;
}
show(a) ;
}
}
原文：http://www.cnblogs.com/lshl/p/5930302.html