#include using namespace std; class Solution { public: vector> fourSum(vector& nums, int target) { set> resultSet; sort(nums.begin(), nums.end()); for (int i = 0; i < nums.size(); i++) { for (int j = i + 1; j < nums.size(); j++) { int l = j + 1, r = nums.size() - 1; while (l < r) { long long sum = (long long)nums[i] + nums[j] + nums[l] + nums[r]; if (sum < target) { l++; } else if (sum > target) { r--; } else { resultSet.insert({nums[i], nums[j], nums[l], nums[r]}); l++; } } } } vector> result; for (auto& e : resultSet) { result.emplace_back(e); } return result; } };