Xor queries of a subarray

Array Bit Manipulation Prefix Sum

78.1% acceptance

Feb 25, 2026

2094

You are given an array arr of positive integers. You are also given the array queries where queries[i] = [lefti, righti]. For each query i compute the XOR of elements from lefti to righti (that is, arr[lefti] XOR arr[lefti + 1] XOR ... XOR arr[righti] ). Return an array answer where answer[i] is the answer to the ith query.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn xor_queries(arr: Vec<i32>, queries: Vec<Vec<i32>>) -> Vec<i32> {
    let n = arr.len();
    let mut prefix = vec![0i32; n + 1];
    for i in 0..n {
      prefix[i + 1] = prefix[i] ^ arr[i];
    }
    queries.iter().map(|q| prefix[q[1] as usize + 1] ^ prefix[q[0] as usize]).collect()
  }
}