2433. Find The Original Array of Prefix Xor

Problem

You are given an integer array pref of size n. Find and return **the array *arr* of size n that satisfies**:

• pref[i] = arr[0] ^ arr[1] ^ ... ^ arr[i].

Note that ^ denotes the bitwise-xor operation.

It can be proven that the answer is unique.

  Example 1:

Input: pref = [5,2,0,3,1]
Output: [5,7,2,3,2]
Explanation: From the array [5,7,2,3,2] we have the following:
- pref[0] = 5.
- pref[1] = 5 ^ 7 = 2.
- pref[2] = 5 ^ 7 ^ 2 = 0.
- pref[3] = 5 ^ 7 ^ 2 ^ 3 = 3.
- pref[4] = 5 ^ 7 ^ 2 ^ 3 ^ 2 = 1.

Example 2:

Input: pref = [13]
Output: [13]
Explanation: We have pref[0] = arr[0] = 13.

  Constraints:

• 1 <= pref.length <= 105

• 0 <= pref[i] <= 106

Solution

/**
 * @param {number[]} pref
 * @return {number[]}
 */
var findArray = function(pref) {
    return pref.map((num, i) => {
        return i === 0
            ? num
            : (num ^ pref[i - 1]);
    });
};

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).