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Grokking the Coding Interview Patterns in Go

Solution: First Missing Positive

Explore how to efficiently find the first missing positive integer in an unsorted array by applying the cyclic sort pattern. Understand how to place elements correctly in linear time and constant space, and learn to identify the missing number with a final pass through the array.

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Statement

Given an unsorted integer array, nums, return the smallest missing positive integer. Create an algorithm that runs with an O(n)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 11.

Constraints:

  • 1≤1 \leq nums.length ≤105\leq 10^5 ...