题解 | #字符统计#

const readline = require('readline');
const rl = readline.createInterface({
    input:process.stdin,
    output:process.stdout
});
rl.on('line',(line)=>{
    let obj = {};
    for(let i of line){
        if(obj[i]){
            obj[i]++;
        }else{
            obj[i] = 1
        }
    }
    const arr = Array.from(new Set(line.split('')));// 去重
    arr.sort((a,b)=>{
        if(obj[a] === obj[b]){
            return a.charCodeAt(0) - b.charCodeAt(0)//升序
        }else{
            return obj[b] - obj[a]//降序
        }
    })

    console.log(arr.join(''))
})