1720. Decode XORed Array

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`.

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`

1720. Decode XORed Array
``````struct Solution;

impl Solution {
fn decode(encoded: Vec<i32>, first: i32) -> Vec<i32> {
let n = encoded.len();
let mut res = vec![first];
for i in 0..n {
res.push(res[i] ^ encoded[i]);
}
res
}
}

#[test]
fn test() {
let encoded = vec![1, 2, 3];
let first = 1;
let res = vec![1, 0, 2, 1];
assert_eq!(Solution::decode(encoded, first), res);
let encoded = vec![6, 2, 7, 3];
let first = 4;
let res = vec![4, 2, 0, 7, 4];
assert_eq!(Solution::decode(encoded, first), res);
}
``````