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by Sumit Chourasia | Jan 10, 2021 | Category :coding | Tags : algorithm array data-structure easy leetcode

Decode XORed Array - Array - Easy - LeetCode

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[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

public class Solution {
    public int[] Decode(int[] encoded, int first) {
        var arr = new int[encoded.Length+1];
        arr[0]=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)