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$ curl repovive.com/roadmaps/data-structures/hash-tables/two-sum-implementation

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$ curl repovive.com/roadmaps/data-structures/hash-tables/two-sum-implementation

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Two Sum - Implementation - Hash Tables | Data Structures | Repovive

Repovive.

Data Structures19 sections · 729 units49h total

Open in Course

Two Sum - Implementation

Complete solution

Here's the solution:

function twoSum(nums, target)
    indexMap := empty hash map  // value -> index

    for i from 0 to length of nums - 1
        complement := target - nums[i]

        if complement in indexMap
            return [indexMap[complement], i]

        indexMap[nums[i]] := i

    return []  // no solution (won't happen per problem)

Time: $O(n)$ . Space: $O(n)$ .