题解 | #字符统计#

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});
rl.on('line', function (line) {
    const tokens = line.split('');
    let arr = [];
    let newArr: {letter: string, count: number}[] = [];
    tokens.forEach((item, index) => {
        if (arr.indexOf(item) === -1) {
            arr.push(item);
            newArr.push({
                letter: item,
                count: 1
            })
        } else {
            const i = arr.indexOf(item);
            newArr[i].count++;
        }
    });
    newArr.sort((a, b) => {
        if (a.count === b.count) {
            return a.letter.charCodeAt(0) - b.letter.charCodeAt(0);
        } else {
            return b.count - a.count;
        }
        
    });
    let result: string[] = [];
    newArr.forEach(item => {
        result.push(item.letter);
    });
    console.log(result.join(''));
});