LeetCode in Kotlin
540. Single Element in a Sorted Array
Medium
You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once.
Return the single element that appears only once.
Your solution must run in O(log n) time and O(1) space.
Example 1:
Input: nums = [1,1,2,3,3,4,4,8,8]
Output: 2
Example 2:
Input: nums = [3,3,7,7,10,11,11]
Output: 10
Constraints:
1 <= nums.length <= 1050 <= nums[i] <= 105
Solution
class Solution {
fun singleNonDuplicate(nums: IntArray): Int {
var start = 0
var end = nums.size - 1
while (start < end) {
val mid = start + (end - start) / 2
if (mid + 1 < nums.size && nums[mid] != nums[mid + 1] && mid - 1 >= 0 && nums[mid] != nums[mid - 1]) {
return nums[mid]
} else if (mid + 1 < nums.size && nums[mid] == nums[mid + 1] && mid % 2 == 0) {
start = mid + 1
} else if (mid - 1 >= 0 && nums[mid] == nums[mid - 1] && mid % 2 == 1) {
start = mid + 1
} else {
end = mid - 1
}
}
return nums[start]
}
}