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$ curl repovive.com/roadmaps/math-fundamentals/big-o-notation/two-sum-implementation

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$ curl repovive.com/roadmaps/math-fundamentals/big-o-notation/two-sum-implementation

Repovive

Two Sum - Implementation - Big O Notation | Math Fundamentals | Repovive

Repovive.

Math Fundamentals18 sections · 842 units13h total

Open in Course

Two Sum - Implementation

(Hash map approach)

function twoSum(arr, target):

map = {}

for i from 0 to arr.length - 1:

    complement = target - arr[i]

    if complement in map:

        return [map[complement], i]

    map[arr[i]] = i

return null

Time: O(n). Space: O(n). This is better than O(n²) brute force.