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### by Sumit Chourasia | Jan 10, 2021 | Category :coding | Tags : algorithmarraydata-structureeasyleetcode #### Decode XORed Array - Array - Easy - LeetCode

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

``````public class Solution {
public int[] Decode(int[] encoded, int first) {
var arr = new int[encoded.Length+1];
arr=first;
for(int i=1;i<encoded.Length+1;i++){
arr[i]=arr[i-1] ^ encoded[i-1];
}

return arr;
}
}``````

Time Complexity: O(n)

Space Complexity: O(n)