LeetCode 1624两个相同字符之间的最长子字符串(java)

class Solution {
    public int maxLengthBetweenEqualCharacters(String s) {
        int size = s.length();
        int res = -1;
        for(int start = 0; start < size - 1; start++) {
            for(int end = start + 1; end < size; end++) {
                char [] sb = s.toCharArray();
                if(sb[start] == sb[end])
                    res = Math.max(res, end - start - 1);
            }
        }
        return res;
    }
}