无重复字符的最长子串

Question

给定一个字符串 s，找出其中不含有重复字符的最长子串的长度，滑动窗口即可

function lengthOfLongestSubstring(s) {
  if (s.length === 0) {
    return 0;
  }
  let l = 0,
    r = 0;
  let maxLen = 1;
  const charMap = {};
  while (r < s.length) {
    if (s[r] in charMap && charMap[s[r]] >= l) {
      l = charMap[s[r]] + 1;
    }

    charMap[s[r]] = r;
    maxLen = Math.max(maxLen, r - l + 1);
    r++;
  }
  return maxLen;
}

console.log(lengthOfLongestSubstring("abcaddcab"));
console.log(lengthOfLongestSubstring("bbbbb"));
console.log(lengthOfLongestSubstring("pwwkew"));

要用 s[r] in charMap 做判断，不能用 charMap[s[r]] 做判断，因为索引为 0 会被判断为 false