# DIY: Kth Missing Positive Number

Solve the interview question "Kth Missing Positive Number" in this lesson.

We'll cover the following

## Problem statement

You are given an array, arr, of positive integers only and an integer, k. The array is sorted in a strictly increasing order. Your task is to find the kth positive integer that is missing from this array.

### Constraints

• 1 <= arr[i] <= 1000
• 1 <= k <= 1000
• arr[i] <= arr[j] for 1 <= i < j <= arr.length

### Input

The input will be an array of positive integers, sorted in ascending order, and an integer, k. The following are examples of the input to the function:

# Sample Input 1:
arr = [1,2,3,4]
k = 2

# Sample Input 2:
arr = [2,3,5,9,10]
k = 4

# Sample Input 3:
arr = [1,97,101,654,798,989,1000]
k = 100


### Output

The output will be an integer. Here are some examples of the output:

# Sample Output 1:
6

# Sample Output 2:
7

# Sample Output 3:
103


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