### Easy
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.
class Solution {
public:
int findKthPositive(vector<int>& arr, int k) {
int i = 0;
int supposed_to_be_item = 1;
while(k > 0 ){
if(supposed_to_be_item != arr[i])
k--;
else if (i < arr.size()-1)
i++;
supposed_to_be_item++;
}
return supposed_to_be_item-1;
}
};