Problem: First Missing Positive

Hard

40 min

Explore how to solve the problem of finding the smallest missing positive integer in an unsorted array. Understand cyclic sort principles to achieve a linear time and constant space solution, enhancing your coding interview skills with pattern recognition and problem-solving strategies.

Statement

Given an unsorted integer array, nums, return the smallest missing positive integer. Create an algorithm that runs with an $O(n)$ time complexity and utilizes a constant amount of space.

Note: The smallest missing positive isn’t the first positive number that’s missing in the range of elements in the input, but the first positive number that’s missing if we start from $1$ .

Constraints:

$1 \leq$ nums.length $\leq 10^5$
$-2^{31} \leq$ nums[i] $\leq 2^{31} - 1$

Problem: First Missing Positive

Hard

40 min

Statement

Given an unsorted integer array, nums, return the smallest missing positive integer. Create an algorithm that runs with an $O(n)$ time complexity and utilizes a constant amount of space.

Note: The smallest missing positive isn’t the first positive number that’s missing in the range of elements in the input, but the first positive number that’s missing if we start from $1$ .

Constraints:

$1 \leq$ nums.length $\leq 10^5$
$-2^{31} \leq$ nums[i] $\leq 2^{31} - 1$

Problem: First Missing Positive

Statement

Examples

Understand the problem

Figure it out!

Try it yourself

Problem: First Missing Positive

Statement

Examples

Understand the problem

Figure it out!

Try it yourself