Python (48 ms, 83.84 %, 13.8 MB, 76.12 %)
Cleanup solution from https://leetcode.com/problems/check-array-formation-through-concatenation/discuss/2356869/Python-3-Easy-solution\npython\nclass Solution:\
Cleanup solution from https://leetcode.com/problems/check-array-formation-through-concatenation/discuss/2356869/Python-3-Easy-solution\n``` python\nclass Solution:\n    def canFormArray(self, arr: List[int], pieces: List[List[int]]) -> bool:\n        hashmap = {piece[0]: piece for piece in pieces}  \n        \n        size: int = len(arr)\n        i = 0    \n        while i < size:\n            if arr[i] not in hashmap:\n                return False\n            lis = hashmap[arr[i]]\n            for l in lis:\n                if l != arr[i]:\n                    return False\n                i += 1\n\n        return True\n```
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