Mistakes in memory management

[Zixiang Li]

There are several mistakes in memory management when utilizing pointer. This could lead to breakdown when a larger number of iterations or solving many instances.

1. Mistake when utilizing Solution**;
   “
   Solution** parents = new Solution * [number_of_parents];
   …….
   delete parents;
   ”
   The memory utilized is not released.
   The correct way:
   “for (int k = 0; k < number_of_parents; k++) {
   delete parents[k];
   }
   delete parents;
   ”

2. Mistake when utilizing vector<Solution*> solutions_;
   “
   vector<Solution*> solutions_
   …….
   solutions_.clear();
   ”
   The memory utilized is not released.
   The correct way:
   “
   for (int i = 0; i < solutions_.size(); i++) {
   delete solutions_[i];
   }
   solutions_.clear();
   ”
   [1] Zixiang Li, Wuhan University of Science and Technology, https://www.researchgate.net/profile/Zixiang-Li-2, [e-mail];

[Antonio J. Nebro]

Dear @zixiangliwust.

Please, could you make a pull request with the suggested changes?