Help please,  I need help to implement the combine function for MergeSort, should work for any size vector and the function should combine the elements from vector A and vector B into vector R. supposed to fill in where it says TODO:   This is the program: // combines two sorted lists A and B into R // displays comparison every time it is done void combine(vector<int> A, vector<int> B, vector<int> &R) {     // TODO: you can find out the size of A using the     // TODO: size function. Treat A and B like arrays.      cout << "comparison" << endl;     // TODO:     // be careful -- R comes in as an empty vector with no slots so you have to use push_back } int main() {   vector<int> L1;   vector<int> L2;   vector<int> L3;   int N;  // how many elements in each of L1 and L2   int e;  // for each element   cout << "How many elements in each list?" << endl;   cin >> N;   cout << "List1"  << endl;   for (int i = 1; i <=N; i++) {     cout << "element :"; cin >> e;     L1.push_back(e);   }   cout << "List2"  << endl;   for (int i = 1; i <=N; i++) {     cout << "element :"; cin >> e;     L2.push_back(e);   }   // TODO: call combine here to combine L1 and L2 into L3   cout << "The result is: ";   for (int i = 0; i < N*2; i++)     { cout << L3[i]; } cout << endl; }// end of main

The concept of pointers in high-level languages was introduced in C programming. Pointers are simply the variables that are used to store memory addresses of another variable. These special variables are generally used in the languages such as C Programm…