無重復字符的最長子串

class Solution {
    public int lengthOfLongestSubstring(String s) {
        Map<Character,Integer> map = new HashMap<>();
        int left = 0,right = 0;
        int max = 0;
        while(right < s.length()){
            if(map.getOrDefault(s.charAt(right),0) != 0){
                map.put(s.charAt(left),map.getOrDefault(s.charAt(left),0) - 1);
                left++;
            }else{
                map.put(s.charAt(right),map.getOrDefault(s.charAt(right),0) + 1);
                right++;
                max = Math.max(max,right - left);
            }
        }
        return max;
    }
}