12345678910111213141516171819
export default function makeGood(s: string): string {    const len = s.length;    const ret: string[] = [];    let i = 0;    while (i < len) {        if (            ret.length > 0 &&            ret[ret.length - 1].toLowerCase() === s.charAt(i).toLowerCase() &&            ret[ret.length - 1] !== s.charAt(i)        ) {            ret.pop();        } else {            ret.push(s.charAt(i));        }        i += 1;    }    return ret.join("");}