class Solution { public: vector> threeSum(vector& nums) meaning

Explanation of the C++ code:

The given code defines a class named "Solution" in C++. This class has a public member function named "threeSum" that takes a vector of integers as input and returns a vector of vectors of integers.

The purpose of this function is to find all unique triplets in the given vector that sum up to zero.

Let's break down the code step by step:

  1. class Solution { - This line begins the definition of the "Solution" class.

  2. public: - This line specifies that the following member functions and variables are accessible from outside the class.

  3. vector> threeSum(vector& nums) - This line declares the "threeSum" member function of the class. It takes a vector of integers named "nums" as input and returns a vector of vectors of integers. The "&" symbol before "nums" indicates that the vector is passed by reference, allowing the function to modify the original vector.

  4. { - This line starts the function body.

  5. // Implementation of the threeSum function goes here - This is a placeholder comment indicating that the implementation of the function should be written here.

  6. } - This line ends the function body.

  7. }; - This line ends the class definition.

The code you provided is a template or skeleton for a class and its member function. The implementation of the "threeSum" function is missing and needs to be filled in with the actual code that finds the triplets summing up to zero.

Please note that without the actual implementation of the "threeSum" function, it is not possible to provide a complete explanation of each step. The code you provided is just a starting point, and the logic and algorithms to find the triplets need to be added to complete the implementation.