Smallest Missing Positive | Dataford Interview Questions

Given an array of size n, how do you find the smallest positive integer that is not present in the array?

Implement first_missing_positive(nums), which receives a mutable list of integers and returns the smallest positive integer absent from it. The expected solution should run in O(n) time and use O(1) extra space; modifying nums is allowed.

Constraints

1 <= nums.length <= 100000
-1000000000 <= nums[i] <= 1000000000
The input list may be modified
Return exactly one positive integer

Function Signature

def first_missing_positive(nums):

Your question is Smallest Missing Positive. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Given an array of size n, how do you find the smallest positive integer that is not present in the array?

Constraints

1 <= nums.length <= 100000
-1000000000 <= nums[i] <= 1000000000
The input list may be modified
Return exactly one positive integer

Function Signature

def first_missing_positive(nums):

Your question is Smallest Missing Positive. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.