Bitwise xor of all pairings

Array Bit Manipulation Brainteaser

66.9% acceptance

Feb 25, 2026

920

You are given two 0-indexed arrays, nums1 and nums2, consisting of non-negative integers. Let there be another array, nums3, which contains the bitwise XOR of all pairings of integers between nums1 and nums2 (every integer in nums1 is paired with every integer in nums2 exactly once). Return the bitwise XOR of all integers in nums3.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn xor_all_nums(nums1: Vec<i32>, nums2: Vec<i32>) -> i32 {
    // Each element of nums1 appears len(nums2) times in nums3.
    // Each element of nums2 appears len(nums1) times in nums3.
    // XOR of x repeated even times = 0; repeated odd times = x.
    let mut ans = 0;
    if nums2.len() % 2 == 1 {
      for &x in &nums1 {
        ans ^= x;
      }
    }
    if nums1.len() % 2 == 1 {
      for &x in &nums2 {
        ans ^= x;
      }
    }
    ans
  }
}