题解 | #字符串合并处理#

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        String line = "";
        if((line = bf.readLine()) != null){
            String[] strs = line.split(" ");
            StringBuilder sb = new StringBuilder();
            for(String str : strs){
                sb.append(str);
            }
            int size = sb.toString().length();
            char[] evens = new char[size % 2 == 1 ? size / 2 + 1 : size / 2];
            char[] odds = new char[size / 2];
            for(int i = 0;i < size;i++){
                if(i % 2 != 1){
                    evens[i / 2] = sb.toString().substring(i,i+1).toCharArray()[0];
                }else{
                    odds[i / 2] = sb.toString().substring(i,i+1).toCharArray()[0];
                }
            }
            Arrays.sort(evens);
            Arrays.sort(odds);
            StringBuilder sbSorted = new StringBuilder();
            for(int i = 0;i < size;i++){
                if(i % 2 != 1){
                    sbSorted.append(evens[i / 2]);
                }else{
                    sbSorted.append(odds[i / 2]);
                }
            }
            HashMap<Character,Character> map = new HashMap<>();
            char[] chs = sbSorted.toString().toCharArray();
            ArrayList<Character> result = new ArrayList();
            for(char c : chs){
                result.add(c);
            }
            map.put('1','8');
            map.put('2','4');
            map.put('3','C');
            map.put('4','2');
            map.put('5','A');
            map.put('7','E');
            map.put('8','1');
            map.put('A','5');
            map.put('B','D');
            map.put('C','3');
            map.put('D','B');
            map.put('E','7');
            map.put('a','5');
            map.put('b','D');
            map.put('c','3');
            map.put('d','B');
            map.put('e','7');
            map.put('f','F');
            for(int i = 0;i < result.size();i++){
                if(map.get(result.get(i)) != null){
                    result.set(i,map.get(result.get(i)));
                }
            }
            StringBuilder resSb = new StringBuilder();
            for(Character c : result){
                resSb.append(c);
            }
            System.out.println(resSb);
        }
    }
}

1. 判断一个数是否奇偶数，可以用以下方式

int num = 1;
if(num % 2 == 0){
	//为偶数
}else{
	//为奇数
}

1. 如果是奇偶数，可以通过String对象的toCharArray转化成为char数组遍历解决

String s = "sdsdadd";
char[] chs = s.toCharArray();
char[] evens = new char[chs.length / 2 + 1];//偶数位元素
char[] odds = new char[chs.length - evens.length];//奇数位元素
int j = 0,k = 0;
for(int i = 0;i < chs.length;i++){
  if(i % 2 == 0){//认为下标从0开始，第一个下标就为偶数位元素
	//为偶数位元素
	evens[j++] = chs[i];
  }else{
	//为奇数位元素
	odds[k++] = chs[i];
  }
}