Ezvor

2433. Find The Original Array of Prefix Xor

MediumArray Preparing judge… LeetCode

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
ArrayBit Manipulation

Hints

Hint 1
Consider the following equation: x ^ a = b. How can you find x?
Hint 2
Notice that arr[i] ^ pref[i-1] = pref[i]. This is the same as the previous equation.