LeetCode in Kotlin

898. Bitwise ORs of Subarrays

Medium

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

Solution

class Solution {
    fun subarrayBitwiseORs(arr: IntArray): Int {
        val set: MutableSet<Int> = HashSet()
        for (i in arr.indices) {
            set.add(arr[i])
            for (j in i - 1 downTo 0) {
                if (arr[i] or arr[j] == arr[j]) {
                    break
                }
                arr[j] = arr[j] or arr[i]
                set.add(arr[j])
            }
        }
        return set.size
    }
}

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