【LeetCode-剑指offer】--16.无重复字符的最长子串

16.无重复字符的最长子串

方法：滑动窗口

class Solution {
    public int lengthOfLongestSubstring(String s) {
        int n = s.length();
        Set<Character> set = new HashSet<>();
        int l = 0,ans = 0;
        for(int i = 0; i < n;i++){
            char ch = s.charAt(i);
            while(set.contains(ch)){
                set.remove(s.charAt(l));
                l++;
            }
            set.add(ch);
            ans = Math.max(ans, i- l + 1);
        }
        return ans;
    }
}