Java 无重复字符的最长子串(滑动窗口+Hash+双指针)

class Solution {
    public int lengthOfLongestSubstring(String s) {
        if(s.length()<=1) {
            return s.length();
        }
        int result=0;
        //通过哈希表来快速定位重复字符的最新位置
        Map<Character,Integer> map = new HashMap<>();
        
        //用快慢指针，快指针指向最新的下标，慢指针指向不重复的最小下标
        int fast =0;
        int slow =0;
        while(fast<s.length()) {
            if(map.containsKey(s.charAt(fast))) {
                slow = Math.max(slow, map.get(s.charAt(fast))+1);
            }
            map.put(s.charAt(fast), fast);
            result = Math.max(result, fast-slow+1);
            fast++;
        }
        
        return result;
    }
}