题解 | #牛群的独特排列#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param s string字符串
     * @return int整型
     */
    public int lengthOfLongestSubstring(String s) {
        int n = s.length();
        Set<Character> set = new HashSet<>();
        int left = 0, right = 0, maxLen = 0;

        while (right < n) {
            if (!set.contains(s.charAt(right))) {
                set.add(s.charAt(right));
                maxLen = Math.max(maxLen, right - left + 1);
                right++;
            } else {
                set.remove(s.charAt(left));
                left++;
            }
        }

        return maxLen;
    }
}