Here's the algorithm. Iterate through the array once. For each number at index : Compute complement = target - nums[] Check if complement exists in your hash map If yes, return [map[complement], ] If no, store nums[] → in the map The trick: you check for the complement BEFORE adding the current element. This prevents matching an element with itself.
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$ curl repovive.com/roadmaps/maang-interview-prep/arrays-hashing/two-sum-solution
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