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 <= 10^50 <= pref[i] <= 10^6
Solution (Java)
class Solution {
public int[] findArray(int[] pref) {
int[] ans=new int[pref.length];
ans[0]=pref[0];
for(int i=1;i<=pref.length-1;i++)
ans[i]=pref[i-1]^pref[i];
return ans;
}
}
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).