3Sum

📜 Problem Statement: Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.

Notice that the solution set must not contain duplicate triplets.

Examples

🔹 Example 1:

Input:

nums = [-1,0,1,2,-1,-4]

Output:

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

Explanation: nums[0] + nums[1] + nums[2] = (-1) + 0 + 1 = 0. nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0. nums[0] + nums[3] + nums[4] = (-1) + 2 + (-1) = 0. The distinct triplets are [-1,0,1] and [-1,-1,2]. Notice that the order of the output and the order of the triplets does not matter.

🔹 Example 2:

Input:

nums = [0,1,1]

Output:

[]

Explanation: The only possible triplet does not sum up to 0.

🔹 Example 3:

Input:

nums = [0,0,0]

Output:

[[0,0,0]]

Explanation: The only possible triplet sums up to 0.

📝 Constraints:

• 3 <= nums.length <= 3000

• -10^5 <= nums[i] <= 10^5