1829. Maximum XOR for Each Query

You are given a sorted array nums of n non-negative integers and an integer maximumBit. You want to perform the following query n times:

  1. Find a non-negative integer k < 2maximumBit such that nums[0] XOR nums[1] XOR ... XOR nums[nums.length-1] XOR k is maximized. k is the answer to the ith query.
  2. Remove the last element from the current array nums.

Return an array answer, where answer[i] is the answer to the ith query.

 

Example 1:

Input: nums = [0,1,1,3], maximumBit = 2
Output: [0,3,2,3]
Explanation: The queries are answered as follows:
1st query: nums = [0,1,1,3], k = 0 since 0 XOR 1 XOR 1 XOR 3 XOR 0 = 3.
2nd query: nums = [0,1,1], k = 3 since 0 XOR 1 XOR 1 XOR 3 = 3.
3rd query: nums = [0,1], k = 2 since 0 XOR 1 XOR 2 = 3.
4th query: nums = [0], k = 3 since 0 XOR 3 = 3.

Example 2:

Input: nums = [2,3,4,7], maximumBit = 3
Output: [5,2,6,5]
Explanation: The queries are answered as follows:
1st query: nums = [2,3,4,7], k = 5 since 2 XOR 3 XOR 4 XOR 7 XOR 5 = 7.
2nd query: nums = [2,3,4], k = 2 since 2 XOR 3 XOR 4 XOR 2 = 7.
3rd query: nums = [2,3], k = 6 since 2 XOR 3 XOR 6 = 7.
4th query: nums = [2], k = 5 since 2 XOR 5 = 7.

Example 3:

Input: nums = [0,1,2,2,5,7], maximumBit = 3
Output: [4,3,6,4,6,7]

 

Constraints:

  • nums.length == n
  • 1 <= n <= 105
  • 1 <= maximumBit <= 20
  • 0 <= nums[i] < 2maximumBit
  • nums​​​ is sorted in ascending order.

Rust Solution

struct Solution;

impl Solution {
    fn get_maximum_xor(nums: Vec<i32>, maximum_bit: i32) -> Vec<i32> {
        let mask: i32 = (1 << maximum_bit) - 1;
        let mut nums: Vec<i32> = nums.into_iter().map(|x| x & mask).collect();
        let mut xor = nums.iter().fold(0, |acc, x| acc ^ x);
        let mut res = vec![];
        while let Some(last) = nums.pop() {
            res.push(mask ^ xor);
            xor ^= last;
        }
        res
    }
}

#[test]
fn test() {
    let nums = vec![0, 1, 1, 3];
    let maximum_bit = 2;
    let res = vec![0, 3, 2, 3];
    assert_eq!(Solution::get_maximum_xor(nums, maximum_bit), res);
    let nums = vec![2, 3, 4, 7];
    let maximum_bit = 3;
    let res = vec![5, 2, 6, 5];
    assert_eq!(Solution::get_maximum_xor(nums, maximum_bit), res);
    let nums = vec![0, 1, 2, 2, 5, 7];
    let maximum_bit = 3;
    let res = vec![4, 3, 6, 4, 6, 7];
    assert_eq!(Solution::get_maximum_xor(nums, maximum_bit), res);
}

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