Introduction

In this blog post, we will explore how to solve the LeetCode problem "898" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Given an integer array arr, return the number of distinct bitwise ORs of all the non-empty subarrays of arr. The bitwise OR of a subarray is the bitwise OR of each integer in the subarray. The bitwise OR of a subarray of one integer is that integer. A subarray is a contiguous non-empty sequence of elements within an array. Example 1: Input: arr = [0] Output: 1 Explanation: There is only one possible result: 0. Example 2: Input: arr = [1,1,2] Output: 3 Explanation: The possible subarrays are [1], [1], [2], [1, 1], [1, 2], [1, 1, 2]. These yield the results 1, 1, 2, 1, 3, 3. There are 3 unique values, so the answer is 3. Example 3: Input: arr = [1,2,4] Output: 6 Explanation: The possible results are 1, 2, 3, 4, 6, and 7. Constraints: 1 <= arr.length <= 5 * 104 0 <= arr[i] <= 109

Explanation

• Iterate through the array: For each element, maintain a set of possible OR values ending at that element.
  • Update the set: For the current element, update the set by taking the bitwise OR of the current element with each of the previous OR values, as well as adding the current element itself.
  • Maintain a global set: Maintain a global set of all distinct OR values encountered so far, and update it with the new OR values generated at each element.

• Runtime Complexity: O(n log(M)), where n is the length of the array and M is the maximum possible value of an element in the array. Since the maximum value is 10^9, log(M) can be considered bounded. Storage Complexity: O(n log(M)), in the worst case where all subarray ORs are distinct.

Code

    def subarrayBitwiseORs(arr):
    """
    Calculates the number of distinct bitwise ORs of all non-empty subarrays of arr.

    Args:
        arr: An integer array.

    Returns:
        The number of distinct bitwise ORs of all non-empty subarrays of arr.
    """

    distinct_ors = set()
    current_ors = set()

    for num in arr:
        new_ors = set()
        new_ors.add(num)
        for prev_or in current_ors:
            new_ors.add(num | prev_or)
        current_ors = new_ors
        distinct_ors.update(current_ors)

    return len(distinct_ors)