Practical Algorithm Implementation | Dataford Interview Questions

Implement a function or algorithm to solve a practical coding challenge with simple, clean logic and edge-case handling.

Implement first_missing_positive(nums), which returns the smallest positive integer absent from the unsorted integer list nums. The function must modify the list in place and use constant extra space.

Contract

Input is a list of integers. Return one integer representing the smallest missing positive value.

Constraints

0 <= nums.length <= 100000
-1000000000 <= nums[i] <= 1000000000
The function must use O(1) extra space
The input list may be modified

Function Signature

def first_missing_positive(nums):

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