LeetCode 1486. XOR Operation in an Array

Description

https://leetcode.com/problems/xor-operation-in-an-array/

Given an integer n and an integer start.

Define an array nums where nums[i] = start + 2*i (0-indexed) and n == nums.length.

Return the bitwise XOR of all elements of nums.

Example 1:

Input: n = 5, start = 0
Output: 8
Explanation: Array nums is equal to [0, 2, 4, 6, 8] where (0 ^ 2 ^ 4 ^ 6 ^ 8) = 8.
Where "^" corresponds to bitwise XOR operator.

Example 2:

Input: n = 4, start = 3
Output: 8
Explanation: Array nums is equal to [3, 5, 7, 9] where (3 ^ 5 ^ 7 ^ 9) = 8.

Example 3:

Input: n = 1, start = 7
Output: 7

Example 4:

Input: n = 10, start = 5
Output: 2

Constraints:

  • 1 <= n <= 1000
  • 0 <= start <= 1000
  • n == nums.length

Explanation

Just keep track of XOR result.

Python Solution

class Solution:
    def xorOperation(self, n: int, start: int) -> int:
        result = 0

        for i in range(n):                
            result = result ^ (start + 2*i)
        
        return result
  • Time Complexity: O(N)
  • Space Complexity: O(1)

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