Python Short DP Solution
\nclass Solution:\n    def maxLength(self, arr: List[str]) -> int:\n        dp=[\'\']\n        res=0\n        for s in arr:\n            for prev in dp:\n      
```\nclass Solution:\n    def maxLength(self, arr: List[str]) -> int:\n        dp=[\'\']\n        res=0\n        for s in arr:\n            for prev in dp:\n                if len(set(s+prev))==len(s)+len(prev):\n                    dp.append(s+prev)\n                    res=max(len(s+prev),res)\n        return res\n```
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