/**

* code by : 老王

* https://github.com/simplemain

*/

import java.util.Set;

import java.util.HashSet;

public class Solution2

{

public static void main(String[] args)

{

final String s = "abcabcbb";

final Solution sol = new Solution2().new Solution();

final int result = sol.lengthOfLongestSubstring(s);

System.out.printf("%d\n", result);

}

class Solution

{

public int lengthOfLongestSubstring(String s)

{

final int len = s.length();

final char[] cs = s.toCharArray();

int maxLen = 0;

for (int p = 0; p < len; p++)

{

final Set<Character> exists = new HashSet<>();

exists.add(cs[p]);

for (int q = p + 1; q < len; q++)

{

final boolean isOK = !exists.contains(cs[q]);

if (!isOK) break;

exists.add(cs[q]);

}

final int curLen = exists.size();

if (curLen > maxLen)

{

maxLen = curLen;

}

}

return maxLen;

}

}

}