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Problem: First Missing Positive

Understand how to find the first missing positive integer in an unsorted array efficiently. Explore the cyclic sort technique that rearranges elements in place to achieve O(n) time complexity and constant space usage. Learn to implement this approach to solve the problem without extra data structures and grasp the underlying logic to apply it in similar array challenges.

Statement

Given an unsorted integer array nums, find and return the smallest positive integer that is not present in nums.

Your solution must run in O(n)O(n) time and use O(1)O(1) auxiliary space.

Constraints:

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