Longest Substring Without Repeating Characters

Given a string, find the length of thelongest substringwithout repeating characters.

Examples:

Given"abcabcbb", the answer is"abc", which the length is 3.

Given"bbbbb", the answer is"b", with the length of 1.

Given"pwwkew", the answer is"wke", with the length of 3. Note that the answer must be asubstring,"pwke"is asubsequenceand not a substring.

Here is a solution.

class Solution {
    public int lengthOfLongestSubstring(String s) {
        // iterate through letters and put all chars into set, until it is found in the set
        // if found in the set, return cursor to previous start + 1 (i-size) and continue reading from there

        int max = 0;
        int count = 0;
        Set<Character> set = new HashSet<>();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (set.contains(c)) {
                int size = set.size();
                set.clear();
                count = 0;
                i = i - size;
            } else {
                set.add(c);
                count++;
                max = Math.max(max, count);
            }
        }

        return max;
    }
}