decode-XORed-array.py

'''
P.S: There is a hidden integer array arr that consists of n non-negative integers.
It was encoded into another integer array encoded of length n - 1, such that encoded[i] = arr[i] XOR arr[i + 1]. For example, if arr = [1,0,2,1], then encoded = [1,2,3].
You are given the encoded array. You are also given an integer first, that is the first element of arr, i.e. arr[0].
Return the original array arr. It can be proved that the answer exists and is unique.
'''

#Solution:
class Solution(object):
    def decode(self, encoded, first):
        """
        :type encoded: List[int]
        :type first: int
        :rtype: List[int]
        """
        arr=[first]
        for elem in range(len(encoded)):
            arr.append(encoded[elem]^arr[elem])
        return arr