1640 Check Array Formation Through Concatenation

1640 Check Array Formation Through Concatenation.py

class Solution:
    def canFormArray(self, arr: List[int], pieces: List[List[int]]) -> bool:
        idx = {}
        for i in range(len(pieces)):
            idx[pieces[i][0]] = i
        cnt = 0
        while cnt < len(arr):
            if arr[cnt] not in idx:
                return False
            p = idx[arr[cnt]]
            for n in pieces[p]:
                if n != arr[cnt]:
                    return False
                cnt += 1       
        
        return True