Problem: Find the First K Missing Positive Numbers

Medium

30 min

Explore how to identify the first k missing positive numbers from an unsorted array by applying cyclic sort techniques. Understand how to handle negative numbers and zeros while ensuring your solution maintains efficient time complexity. This lesson helps you develop a method to solve such problems optimally and prepares you to implement these concepts confidently.

Statement

Given an unsorted integer array, arr, of size n and an integer k, find the first k missing positive integers from the array, ignoring all negative numbers and zeros.

If the array does not contain enough missing positive numbers, add the next consecutive positive integers, starting from the smallest number greater than the largest value in the array, until exactly k missing positive numbers have been found.

Return the list of the first k missing positive integers, sorted in ascending order.

Constraints:

$n =$ arr.length
$1 \leq k \leq 10^4$
$-10^4 \leq$ arr[i] $\leq 10^4$
$0 \leq n \leq 10^4$

Problem: Find the First K Missing Positive Numbers

Medium

30 min

Statement

Given an unsorted integer array, arr, of size n and an integer k, find the first k missing positive integers from the array, ignoring all negative numbers and zeros.

Return the list of the first k missing positive integers, sorted in ascending order.

Constraints:

$n =$ arr.length
$1 \leq k \leq 10^4$
$-10^4 \leq$ arr[i] $\leq 10^4$
$0 \leq n \leq 10^4$

Problem: Find the First K Missing Positive Numbers

Statement

Examples

Understanding the problem

Figure it out!

Try it yourself

Problem: Find the First K Missing Positive Numbers

Statement

Examples

Understanding the problem

Figure it out!

Try it yourself