3Sum 25 XP Medium

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Given an array nums, return all unique triplets [nums[i], nums[j], nums[k]] such that i != j != k and nums[i] + nums[j] + nums[k] == 0.

The solution must not contain duplicate triplets.

nums = [-1, 0, 1, 2, -1, -4]
# Output: [[-1, -1, 2], [-1, 0, 1]]

Strategy: Sort the array, then for each number, use Two Sum II (two pointers) on the remaining elements. Skip duplicates to avoid repeats.

📋 Instructions

Implement `three_sum(nums)` that returns all unique triplets summing to 0. Test with `nums = [-1, 0, 1, 2, -1, -4]`. Print the sorted result.

Sort the array first! Then use two pointers inside a loop. Skip duplicates to avoid repeated triplets. For each number, find two others that sum to its negative.

🧪 Test Cases

Input

three_sum([-1, 0, 1, 2, -1, -4])

Expected

[[-1, -1, 2], [-1, 0, 1]]

Test case 1

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main.py

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Output

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