# 1720. Decode XORed Array

https://leetcode.com/problems/decode-xored-array

## Description

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] <= 105`
* `0 <= first <= 105`

## ac

```java
```
