Ezvor

3097. Shortest Subarray With OR at Least K II

MediumArray Preparing judge… LeetCode

You are given an array nums of non-negative integers and an integer k.

An array is called special if the bitwise OR of all of its elements is at least k.

Return the length of the shortest special non-empty subarray of nums, or return -1 if no special subarray exists.

 

Example 1:

Input: nums = [1,2,3], k = 2

Output: 1

Explanation:

The subarray [3] has OR value of 3. Hence, we return 1.

Example 2:

Input: nums = [2,1,8], k = 10

Output: 3

Explanation:

The subarray [2,1,8] has OR value of 11. Hence, we return 3.

Example 3:

Input: nums = [1,2], k = 0

Output: 1

Explanation:

The subarray [1] has OR value of 1. Hence, we return 1.

 

Constraints:

  • 1 <= nums.length <= 2 * 105
  • 0 <= nums[i] <= 109
  • 0 <= k <= 109
ArrayBit ManipulationSliding Window

Hints

Hint 1
For each nums[i], we can maintain each subarray’s bitwise OR result ending with it.
Hint 2
The property of bitwise OR is that it never unsets any bits and only sets new bits
Hint 3
So the number of different results for each nums[i] is at most the number of bits 32.