不重复最长字符串

输出 给定字符串中 不重复的最长字串的 字符个数

public static int lengthOfLongestSubstring(String str){

        if (str == null || "".equals(str)){
            return 0;
        }
        char[] chars = str.toCharArray();


        return 0;
    }
    public int lengthOfLongestSubstring_(String s) {
        if(s == null || s.equals("")){
            return 0;
        }
        char[] arr = s.toCharArray();
        int left = 0;
        int right = 0;
        int max = 0;
        boolean visited []  = new boolean[128];
        while(right < arr.length ){
            if(visited[(int)arr[right]] == false){
                visited[(int)arr[right]] = true;
                right++;
            }else{
                max = Math.max(max,right - left);
                while (left < right && arr[right] != arr[left]){
                    visited[(int)arr[left]] = false;
                    left ++;
                }
                left++;
                right++;
            }
        }
        max = Math.max(max,right - left);
        return max;
    }

结果测试

public static void main(String[] args) {

    String str = "abcabcdabcdeabcde";
    System.out.println(new LengthOfLongestSubstring().lengthOfLongestSubstring_(str));
}