Given an array of strings arr. String s is a concatenation of a sub-sequence of arr which have unique characters.
Return the maximum possible length of s.
Example 1:
Input: arr = ["un","iq","ue"]
Output: 4
Explanation: All possible concatenations are "","un","iq","ue","uniq" and "ique".
Maximum length is 4.
Example 2:
Input: arr = ["cha","r","act","ers"]
Output: 6
Explanation: Possible solutions are "chaers" and "acters".
Example 3:
Input: arr = ["abcdefghijklmnopqrstuvwxyz"]
Output: 26
Constraints:
1 <= arr.length <= 161 <= arr[i].length <= 26arr[i]contains only lower case English letters.