题解 | #删除字符串中出现次数最少的字符#

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

rl.on('line', function (line) {
    let charLen = {};
    for(let i = 0; i < line.length; i++) {
        charLen[line[i]] = charLen[line[i]] ? charLen[line[i]] + 1 : 1;
    }

    let minCharLen = {};
    let minLen = 20;
    for (let char in charLen) {
        if (charLen[char] === minLen) {
            minCharLen[char] = charLen[char];
        } else if (charLen[char] < minLen) {
            minLen = charLen[char];
            minCharLen = {};
            minCharLen[char] = charLen[char];
        }
    }

    for (let char in minCharLen) {
        const reg = new RegExp(char,'g');
        line = line.replace(reg, '')
    }

    console.log(line);
});