Formatted question description: https://leetcode.ca/all/1486.html

1486. XOR Operation in an Array (Easy)

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

Related Topics:
Array, Bit Manipulation

Solution 1.

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

// Time: O(N)
// Space: O(1)
class Solution {
public:
    int xorOperation(int n, int start) {
        int ans = 0;
        for (int i = 0; i < n; ++i) ans ^= start + 2 * i;
        return ans;
    }
};

Java

class Solution {
    public int xorOperation(int n, int start) {
        int end = start + 2 * (n - 1);
        int xor = 0;
        for (int i = start; i <= end; i += 2)
            xor ^= i;
        return xor;
    }
}

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