算法面试题：无重复字符的最长子串
lettcode算法面试题：
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。
public static void main(String[] args) {
lengthOfLongestSubstring("abcabcbb");
}
public static int lengthOfLongestSubstring(String s) {
if (s.length() <=1){
return s.length();
}
Set<Character> cList = new HashSet<Character>();
int ret = 0;
for (int i = 0; i < s.length()-1; i++) {
cList.clear();
Character chi = s.charAt(i);
cList.add(chi);
for(int j = i+1; j < s.length();j++){
Character chj = s.charAt(j);
if(!cList.contains(chj)){
cList.add(chj);
if(j == s.length()-1){
ret = Math.max(ret, cList.size());
}
}else {
ret = Math.max(ret, cList.size());
break;
}
}
}
return ret;
}