cpp-flashcards/org/study_deck_02/dsa/two-pointers/0015-3sum.org

#+ANKI_DECK: study_deck_02
* TODO 0015. 3Sum :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0015. 3Sum][0015. 3Sum]]
:END:

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.

*Example 1:*


#+begin_src
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.
#+end_src


*Example 2:*


#+begin_src
Input: nums = [0,1,1]
Output: []
Explanation: The only possible triplet does not sum up to 0.
#+end_src


*Example 3:*


#+begin_src
Input: nums = [0,0,0]
Output: [[0,0,0]]
Explanation: The only possible triplet sums up to 0.
#+end_src


*Constraints:*

 - ~3 <= nums.length <= 3000~

 - ~-10^{5} <= nums[i] <= 10^{5}~

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Solution:
    def threeSum(self, nums: list[int]) -> list[list[int]]:
#+end_src

** TODO C++
#+begin_src cpp
class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        
    }
};
#+end_src