Missing First Positive Integer | Dataford Interview Questions

How would you find the missing first positive integer in an array?

Implement def first_missing_positive(nums):, returning the smallest positive integer not present in the input array. The solution should run in O(n) time and use O(1) extra space, excluding the input array.

Constraints

0 <= nums.length <= 10^5
-10^9 <= nums[i] <= 10^9
The input array may contain duplicates.
The algorithm may modify nums in place.

Function Signature

def first_missing_positive(nums):

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

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Problem

How would you find the missing first positive integer in an array?

Constraints

0 <= nums.length <= 10^5
-10^9 <= nums[i] <= 10^9
The input array may contain duplicates.
The algorithm may modify nums in place.

Function Signature

def first_missing_positive(nums):

Your question is Missing First Positive Integer. 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.