Question

2683. Neighboring Bitwise XOR

中文文档

Description

A 0-indexed array derived with length n is derived by computing the bitwise XOR (⊕) of adjacent values in a binary array original of length n.

Specifically, for each index i in the range [0, n - 1]:

• If i = n - 1, then derived[i] = original[i] ⊕ original[0].
• Otherwise, derived[i] = original[i] ⊕ original[i + 1].

Given an array derived, your task is to determine whether there exists a valid binary array original that could have formed derived.

Return _true if such an array exists or false otherwise._

• A binary array is an array containing only 0's and 1's

 

Example 1:

Input: derived = [1,1,0]
Output: true
Explanation: A valid original array that gives derived is [0,1,0].
derived[0] = original[0] ⊕ original[1] = 0 ⊕ 1 = 1 
derived[1] = original[1] ⊕ original[2] = 1 ⊕ 0 = 1
derived[2] = original[2] ⊕ original[0] = 0 ⊕ 0 = 0

Example 2:

Input: derived = [1,1]
Output: true
Explanation: A valid original array that gives derived is [0,1].
derived[0] = original[0] ⊕ original[1] = 1
derived[1] = original[1] ⊕ original[0] = 1

Example 3:

Input: derived = [1,0]
Output: false
Explanation: There is no valid original array that gives derived.

 

Constraints:

• n == derived.length
• 1 <= n <= 105
• The values in derived are either 0's or 1's

Solutions

Solution 1

class Solution:
  def doesValidArrayExist(self, derived: List[int]) -> bool:
    return reduce(xor, derived) == 0

class Solution {
  public boolean doesValidArrayExist(int[] derived) {
    int s = 0;
    for (int x : derived) {
      s ^= x;
    }
    return s == 0;
  }
}

class Solution {
public:
  bool doesValidArrayExist(vector<int>& derived) {
    int s = 0;
    for (int x : derived) {
      s ^= x;
    }
    return s == 0;
  }
};

func doesValidArrayExist(derived []int) bool {
  s := 0
  for _, x := range derived {
    s ^= x
  }
  return s == 0
}

function doesValidArrayExist(derived: number[]): boolean {
  let s = 0;
  for (const x of derived) {
    s ^= x;
  }
  return s === 0;
}

Solution 2

function doesValidArrayExist(derived: number[]): boolean {
  return derived.reduce((acc, x) => acc ^ x, 0) === 0;
}