LeetCode in Kotlin
2150. Find All Lonely Numbers in the Array
Medium
You are given an integer array nums. A number x is lonely when it appears only once, and no adjacent numbers (i.e. x + 1 and x - 1) appear in the array.
Return all lonely numbers in nums. You may return the answer in any order.
Example 1:
Input: nums = [10,6,5,8]
Output: [10,8]
Explanation:
-
10 is a lonely number since it appears exactly once and 9 and 11 does not appear in nums.
-
8 is a lonely number since it appears exactly once and 7 and 9 does not appear in nums.
-
5 is not a lonely number since 6 appears in nums and vice versa.
Hence, the lonely numbers in nums are [10, 8].
Note that [8, 10] may also be returned.
Example 2:
Input: nums = [1,3,5,3]
Output: [1,5]
Explanation:
-
1 is a lonely number since it appears exactly once and 0 and 2 does not appear in nums.
-
5 is a lonely number since it appears exactly once and 4 and 6 does not appear in nums.
-
3 is not a lonely number since it appears twice.
Hence, the lonely numbers in nums are [1, 5].
Note that [5, 1] may also be returned.
Constraints:
1 <= nums.length <= 1050 <= nums[i] <= 106
Solution
class Solution {
fun findLonely(nums: IntArray): List<Int> {
val ans: MutableList<Int> = ArrayList()
val m = HashMap<Int, Int>()
for (i in nums) {
m[i] = m.getOrDefault(i, 0) + 1
}
for (i in nums) {
if (m[i] == 1 && !m.containsKey(i - 1) && !m.containsKey(i + 1)) {
ans.add(i)
}
}
return ans
}
}