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.
Example 1:
Input: encoded = [1,2,3], first = 1
Output: [1,0,2,1]
Explanation: If arr = [1,0,2,1], then first = 1 and encoded = [1 XOR 0, 0 XOR 2, 2 XOR 1] = [1,2,3]
Example 2:
Input: encoded = [6,2,7,3], first = 4
Output: [4,2,0,7,4]
Constraints:
- 2 <= n <= 104
- encoded.length == n – 1
- 0 <= encoded[i] <= 10^5
- 0 <= first <= 10^5
Solution in python:
class Solution:
def decode(self, encoded: List[int], first: int) -> List[int]:
result = [first for i in range(len(encoded)+1)]
for i in range(len(encoded)):
result[i+1] = encoded[i]^result[i]
return result
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