3.无重复字符的最长子串

给定一个字符串，请你找出其中不含有重复字符的 最长子串 的长度。

解题思路：使用queue的思想来解题；

class Solution {
    public int lengthOfLongestSubstring(String s) {
        int result = 0;
        char[] charList = s.toCharArray();
        StringBuilder stringQueue = new StringBuilder();
        for(int i = 0; i < s.length(); i++){
            int index = stringQueue.toString().indexOf(charList[i]);
            if(index >= 0){
                result = result > stringQueue.toString().length() ? result : stringQueue.toString().length();
                if(index == 0){
                    stringQueue.deleteCharAt(0);
                }else {
                    stringQueue.delete(0, index+1);
                }
            }
            stringQueue.append(charList[i]);
        }
        result = result > stringQueue.toString().length() ? result : stringQueue.toString().length();
        return result;
    }
}