<p>Given an integer array nums, return all the triplets <code>[nums[i], nums[j], nums[k]]</code> such that <code>i != j</code>, <code>i != k</code>, and <code>j != k</code>, and <code>nums[i] + nums[j] + nums[k] == 0</code>.</p>

<p>Notice that the solution set must not contain duplicate triplets.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [-1,0,1,2,-1,-4]
<strong>Output:</strong> [[-1,-1,2],[-1,0,1]]
<strong>Explanation:</strong> 
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.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [0,1,1]
<strong>Output:</strong> []
<strong>Explanation:</strong> The only possible triplet does not sum up to 0.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [0,0,0]
<strong>Output:</strong> [[0,0,0]]
<strong>Explanation:</strong> The only possible triplet sums up to 0.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>3 &lt;= nums.length &lt;= 3000</code></li>
	<li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    struct CompareByFirstElement {
    bool operator() (const std::tuple<int, int>& a, const std::tuple<int, int>& b) const {
    return std::get<0>(a) < std::get<0>(b);
}
    };
    vector<vector<int>> threeSum(vector<int>& nums) {
        std::vector<std::tuple<int, int>> vec ;
        for(unsigned int i = 0; i < nums.size(); ++i){
            vec.push_back(std::make_tuple(nums[i], i));
        }
        std::sort(vec.begin(), vec.end(), CompareByFirstElement());
        std::set<std::vector<int>> out;
        for(int i = 0; i < nums.size() - 2; ++i){
            int target = -nums[i];
            int left = 0;
            int right = nums.size()-1;
            while(left<right){
                if(std::get<1>(vec[left]) <= i){
                    ++left;
                }else if(std::get<1>(vec[right]) <= i){
                    --right;
                }else{
                    int t = std::get<0>(vec[left]) + std::get<0>(vec[right]);
                    if(t < target){
                        ++left;
                    }else if(t>target){
                        --right;
                    }else{
                        std::vector<int> temp = {nums[i],std::get<0>(vec[left]),std::get<0>(vec[right])};
                        std::sort(temp.begin(),temp.end());
                        out.insert(temp);
                        --right;
                        ++left;
                    }
                }
            }
        }
        std::vector<std::vector<int>> o (out.begin(),out.end());
        return o;
    }
};
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