Given an array arr of positive integers sorted in a strictly increasing order, and an integer k.
Find 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 <= 1000
1 <= arr[i] <= 1000
1 <= k <= 1000
arr[i] < arr[j] for 1 <= i < j <= arr.length
Solution:
class Solution {
public int findKthPositive(int[] arr, int k) {
int p = 0, n = 0, i = 1;
for (; i <= 2000; i ++) {
if (p >= arr.length || arr[p] != i) {
n ++;
} else {
p ++;
}
if (n == k) break;
}
return i;
}
}