题解 | #提取不重复的整数#

倒着循环，利用对象去重

const str = readline();
const obj = {};
const arr = [];
for (let i = str.length - 1; i >= 0 && arr.length <= 10; i--) {
  const n = str[i];
  if (!obj[n]) {
    arr.push(n);
    obj[n] = true;
  }
}
console.log(arr.join(""));