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Solution: First Missing Positive

Explore how to efficiently solve the first missing positive problem in an unsorted array using cyclic sort. Learn to place numbers in their correct positions in O(n) time and constant space, enabling you to identify the smallest missing positive integer without extra storage or sorting overhead.

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:

  • 11 \leq nums.length 105\leq 10^5 ...