1539. Kth Missing Positive Number
Easy
Given an array
arr of positive integers sorted in a strictly increasing order, and an integer k.Return the
kth positive integer that is missing from this array.Example 1:
Input: arr = [2,3,4,7,11], k = 5
Output:
9
Explanation:
The missing positive integers are [1,5,6,8,9,10,12,13,...]. The 5th missing positive integer is 9.
Example 2:
Input: arr = [1,2,3,4], k = 2
Output:
6
Explanation:
The missing positive integers are [5,6,7,...]. The 2nd missing positive integer is 6.
Constraints:
1 <= arr.length <= 10001 <= arr[i] <= 10001 <= k <= 1000arr[i] < arr[j]for1 <= i < j <= arr.length
Follow up:
Could you solve this problem in less than O(n) complexity?
func findKthPositive(arr []int, k int) int {
l := arr[len(arr)-1]
nums := make([]bool, l)
for _, n := range arr {
nums[n-1] = true
}
count := 0
for i, n := range nums {
if !n {
count++
}
if count == k { return i+1 }
}
return (k-count) + l
}