Optimizing Two Sum with Sorted Arrays in O(1) Space

Why Sorting Changes Everything: Two Sum in O(1) Space The classic Two Sum problem typically requires a HashMap for O(n) time and O(n) space. But when the input is already sorted, a completely different approach emerges: two pointers converging from opposite ends. The key insight: if the current sum is too large, the right pointer must move left (smaller values); if too small, the left pointer must move right (larger values). This eliminates the need for any auxiliary data structure. The Real Lesson: Data properties unlock different algorithmic approaches. Sorted data enables two-pointer techniques, eliminating space overhead. This same principle applies across domains — leveraging pre-existing order (timestamps in logs, sorted database indices) can transform O(n) space solutions into O(1) space with the same time complexity. Time: O(n) | Space: O(1) #AlgorithmOptimization #TwoPointers #SortedArrays #SpaceComplexity #Python #CodingInterview #SoftwareEngineering

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