1239. Maximum Length of a Concatenated String with Unique Characters

https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters

Description

You are given an array of strings arr. A string s is formed by the concatenation of a subsequence of arr that has unique characters.

Return the maximum possible length of s.

A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.

Example 1:

**Input:** arr = ["un","iq","ue"]
**Output:** 4
**Explanation:** All the valid 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 <= 16

• 1 <= arr[i].length <= 26

• arr[i] contains only lower case English letters.

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