Solution Review: Problem Challenge 3

Find the First K Missing Positive Numbers (hard)

Given an unsorted array containing numbers and a number ‘k’, find the first ‘k’ missing positive numbers in the array.

Example 1:

Input: [3, -1, 4, 5, 5], k=3
Output: [1, 2, 6]
Explanation: The smallest missing positive numbers are 1, 2 and 6.

Example 2:

Input: [2, 3, 4], k=3
Output: [1, 5, 6]
Explanation: The smallest missing positive numbers are 1, 5 and 6.

Example 3:

Input: [-2, -3, 4], k=2
Output: [1, 2]
Explanation: The smallest missing positive numbers are 1 and 2.

Solution

This problem follows the Cyclic Sort pattern and shares similarities with Find the Smallest Missing Positive Number. The only difference is that, in this problem, we need to find the first ‘k’ missing numbers compared to only the first missing number.

We will ...