奇数位按升序排序，偶数位按降序排序

import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
while(scan.hasNext()){
String str = scan.nextLine();
sort(str);
}
scan.close();
}
private static void sort(String str){
//去掉空格，保存数字
int str_length = str.length();
StringBuilder sb = new StringBuilder();
for(int i = 0 ; i < str_length ; i++){
if(str.charAt(i) != ' '){
sb.append(str.charAt(i));
}
}
char[] num = sb.toString().toCharArray();

int length = num.length;

int part_length = length / 2;//保存一半数字，按照奇数偶数保存
char[] odd;
char[] even;
//偶数个数字
if(length % 2 == 0){
odd = new char[part_length]; 
even = new char[part_length];
}else{
//奇数个数字,多一个奇数
odd = new char[part_length + 1];
even = new char[part_length];
}
int index_odd = 0;
int index_even = 0;
for(int i = 0 ; i < length ; i++){
if(i % 2 == 0){

odd[index_odd++] = num[i];
}else{
even[index_even++] = num[i];
}
} 
ascendingSort(odd);//奇数位升序
descendingSort(even);//偶数位降序

for(int i = 0 ; i < index_even ; i++){
if(i == 0)  System.out.print(odd[i] + " " + even[i]);
else System.out.print(" " + odd[i] + " " + even[i]);
}
if(index_odd != index_even){
System.out.println(" " +odd[index_odd - 1]);
}
}
private static void ascendingSort(char[] data){
int length = data.length;
char temp = '*';
for(int i = 0 ; i < length - 1 ; i++){
for(int j = i + 1 ; j < length ; j++){
if(data[i] > data[j]){
temp = data[i];
data[i] = data[j];
data[j] = temp;
}
}
}
}
private static void descendingSort(char[] data){
int length = data.length;
char temp = '*';
for(int i = 0 ; i < length - 1 ; i++){
for(int j = i + 1 ; j < length ; j++){
if(data[i] < data[j]){
temp = data[i];
data[i] = data[j];
data[j] = temp;
}
}
}
} 
}