题解 | #字符串合并处理#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    const str = (await readline()).split(" ").join("");
    //分开奇偶位并分别按ascii码排序
    let odd = "",even = "";
    for(let i = 0; i < str.length; i++){
        if(i&1) even += str.charAt(i);
        else  odd += str.charAt(i);
    }
    odd = odd.split("").sort().join("");
    even = even.split("").sort().join("");

    // 转换
    const transfer = (c) =>{
        let num = 0;
        if(c>="0"&&c<="9") num = c.charCodeAt()-"0".charCodeAt();
        else if(c>="a"&&c<="f") num = c.charCodeAt()-"a".charCodeAt()+10;
        else if(c>="A"&&c<="F") num = c.charCodeAt()-"A".charCodeAt()+10;
        else return c;//其他字符不转换，坑死
        num = parseInt(num.toString(2).padStart(4,0).split("").reverse().join(""),2);
        if(num<10) return String(num);
        else return String.fromCharCode("A".charCodeAt()+num-10);
    }
    //处理转换
    let res = "",i = 0, j = 0;
    while(i<odd.length){
        res += transfer(odd.charAt(i++));
        j < even.length && (res += transfer(even.charAt(j++)));
    }
    console.log(res);
}()