LeetCode in Kotlin
2568. Minimum Impossible OR
Medium
You are given a 0-indexed integer array nums.
We say that an integer x is expressible from nums if there exist some integers 0 <= index1 < index2 < ... < indexk < nums.length for which nums[index1] | nums[index2] | ... | nums[indexk] = x. In other words, an integer is expressible if it can be written as the bitwise OR of some subsequence of nums.
Return the minimum positive non-zero integer that is not expressible from nums.
Example 1:
Input: nums = [2,1]
Output: 4
Explanation: 1 and 2 are already present in the array. We know that 3 is expressible, since nums[0] | nums[1] = 2 | 1 = 3. Since 4 is not expressible, we return 4.
Example 2:
Input: nums = [5,3,2]
Output: 1
Explanation: We can show that 1 is the smallest number that is not expressible.
Constraints:
1 <= nums.length <= 1051 <= nums[i] <= 109
Solution
class Solution {
fun minImpossibleOR(nums: IntArray): Int {
val pow2s = nums.filter {
it and (it - 1) == 0
}.toSet()
return 1 shl (0..31).first {
(1 shl it) !in pow2s
}
}
}