/*
 * @lc app=leetcode id=3 lang=java
 *
 * [3] Longest Substring Without Repeating Characters
 */

// @lc code=start
class Solution {
    public int lengthOfLongestSubstring(String s) {
        if(s.length() == 0) {
            return 0;
        }
        Set<Character> chs = new HashSet<>();
        int i = 0, j = 0, r = 0, cur = 0;
        while(j < s.length()) {
            if(!chs.contains(s.charAt(j))) {
                chs.add(s.charAt(j));
                cur++;
                if(cur > r) {
                    r = cur;
                }
            } else {
                while(s.charAt(i) != s.charAt(j)) {
                    chs.remove(s.charAt(i));
                    i++;
                }
                i++;
                cur = j - i + 1;
                if(cur > r) {
                    r = cur;
                }
            }
            j++;
        }
        return r;
    }
}
// @lc code=end