在一个函数中颠倒字符串并删除重复元素

function reverseAndRemoveDuplicates(str) {
  let chars = str.split('');
  let left = 0;
  let right = chars.length - 1;

  // 颠倒字符串
  while (left < right) {
    let temp = chars[left];
    chars[left] = chars[right];
    chars[right] = temp;
    left++;
    right--;
  }

  let uniqueChars = new Set();
  let result = [];

  // 删除重复元素
  for (let i = 0; i < chars.length; i++) {
    if (!uniqueChars.has(chars[i])) {
      uniqueChars.add(chars[i]);
      result.push(chars[i]);
    }
  }

  return result.join('');
}

const input = 'abbaccdd';
const output = reverseAndRemoveDuplicates(input);
console.log(output); // 输出：dcba