Find the K-or of an Array(LeetCode 2917):

Problem

You are given an integer array nums, and an integer k. Let's introduce K-or operation by extending the standard bitwise OR. In K-or, a bit position in the result is set to 1 if at least k numbers in nums have a 1 in that position.

Return the K-or of nums.

 

Example 1:

Input: nums = [7,12,9,8,9,15], k = 4

Output: 9

Explanation:

Represent numbers in binary:

Number Bit 3 Bit 2 Bit 1 Bit 0
7 0 1 1 1
12 1 1 0 0
9 1 0 0 1
8 1 0 0 0
9 1 0 0 1
15 1 1 1 1
Result = 9 1 0 0 1

Bit 0 is set in 7, 9, 9, and 15. Bit 3 is set in 12, 9, 8, 9, and 15.
Only bits 0 and 3 qualify. The result is (1001)2 = 9.

Example 2:

Input: nums = [2,12,1,11,4,5], k = 6

Output: 0

Explanation: No bit appears as 1 in all six array numbers, as required for K-or with k = 6. Thus, the result is 0.

Example 3:

Input: nums = [10,8,5,9,11,6,8], k = 1

Output: 15

Explanation: Since k == 1, the 1-or of the array is equal to the bitwise OR of all its elements. Hence, the answer is 10 OR 8 OR 5 OR 9 OR 11 OR 6 OR 8 = 15.

 

Constraints:

  • 1 <= nums.length <= 50
  • 0 <= nums[i] < 231
  • 1 <= k <= nums.length