题解 | #提取不重复的整数#

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();
    const set = new Set();
    const len = str.length;
    let res = "";
    for(let i = len-1; i >= 0; i--){
        const c = str.charAt(i);
        if(!set.has(c)) res += c;
        set.add(c);
    }
    console.log(res);    
}()