First Missing Positive

To find the smallest positive number missing from an unsorted array, various approaches can be applied. The naive method sorts the array, while more efficient solutions use techniques like cycle sort or marking indices. Another approach involves negating array elements or using a visited array to track which numbers are present. These solutions have different time and space complexities, but all aim to find the first missing positive number. The cycle sort approach optimizes the space complexity to O(1) while maintaining O(n) time complexity.

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