Python's 🐍 Simple and Easy to Understand Solution ||99% Faster 🔥||
\n\n# Intuition\n\nTo find the maximum length of a concatenated string with unique characters, we can use a backtracking approach. The idea is to iterate throug
![image.png](https://assets.leetcode.com/users/images/4344986f-85c1-4c6b-aee8-eba9a864793a_1705986073.1400738.png)\n\n# Intuition\n\nTo find the maximum length of a concatenated string with unique characters, we can use a backtracking approach. The idea is to iterate through all possible subsequences of the given array of strings and check if the concatenation of any subsequence results in a string with unique characters. We need to keep track of the unique characters while exploring different subsequences.\n\n# Approach\n1. The ***is_unique*** function checks if a given subsequence has unique characters by comparing its length with the length of the set of characters in the subsequence.\n2. The ***backtrack*** function recursively generates all possible subsequences, and for each valid subsequence, it updates the maximum length if the current subsequence has unique characters.\n3. The main function initializes the maximum length to 0 and calls the ***backtrack*** function to explore all possible combinations.\n\n# Complexity\n- Time complexity:\n-O(2^n)\n\n- Space complexity:\n-O(n)\n\n# Code\n```\nclass Solution:\n    def maxLength(self, arr: List[str]) -> int:\n        def is_unique(subseq):\n            return len(subseq) == len(set(subseq))\n        def backtrack(start, current_subseq):\n            nonlocal max_length\n            if is_unique(current_subseq):\n                max_length = max(max_length, len(current_subseq))\n            for i in range(start, len(arr)):\n                backtrack(i + 1, current_subseq + arr[i])\n        max_length = 0\n        backtrack(0, "")\n        return max_length\n```\n![uv.jpeg](https://assets.leetcode.com/users/images/c7cc905f-6c30-403f-8fdf-fb88cf65af73_1705986192.1572044.jpeg)\n
['Python3']