LeetCode-in-Java
2433. Find The Original Array of Prefix Xor
Medium
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 <= 1050 <= pref[i] <= 106
Solution
public class Solution {
public int[] findArray(int[] pref) {
int[] result = new int[pref.length];
result[0] = pref[0];
for (int i = 1; i < pref.length; i++) {
result[i] = pref[i] ^ pref[i - 1];
}
return result;
}
}