Now, you create the function that searches for the first solution.

Add the following code after the comment //Find the first solution

IloBool RoutingSolver::findFirstSolution() {
  if (!_solver.solve(_goal)) {
    _solver.error() << "Infeasible Routing Plan" << endl;
    return IloFalse;
  }

You use the member function IloSolver::solve to search for a solution using _goal. This goal searches for a first solution using the savings heuristic. It then finds the cost associated with this first solution.

Next, you use the member function IloRoutingSolution::store to store the solution and its cost. These will be used in the solution improvement phase.

Add the following code after the comment //Store the first solution

  _solution.store(_solver);
  return IloTrue;
}