Longest Substring Without Repeating Characters

1public int lengthOfLongestSubstring(String s) {
2    int maxLen = 0;
3    int left = 0;
4    Set<Character> charSet = new HashSet<>();
5
6    for (int right = 0; right < s.length(); right++) {
7        while (charSet.contains(s.charAt(right))) {
8            charSet.remove(s.charAt(left));
9            left++;
10        }
11        charSet.add(s.charAt(right));
12        maxLen = Math.max(maxLen, right - left + 1);
13    }
14
15    return maxLen;
16}