greedy

package il.ac.tau.cs.sw1.ex7;

import java.util.*;


public interface Greedy<T>{

    /**
     * A selection function, which chooses the best candidate to be added to the solution
     */
    Iterator<T> selection();

    /**
     * A feasibility function, that is used to determine if a candidate can be used to contribute to a solution
     */
    boolean feasibility(List<T> lst, T element);

    /**
     * An assign function, which assigns a value to a solution, or a partial solution
     */
    void assign(List<T> lst, T element);

    /**
     * A solution function, which will indicate when we have discovered a complete solution
     */
    boolean solution(List<T> lst);

    /**
     * The Greedy Algorithm
     */
    default List<T> greedyAlgorithm(){
        ArrayList<T> candidates_list = new ArrayList<T>(); // empty list
        Iterator<T> selection = selection();
        T element;
        while (selection.hasNext()) { // selection has more elements
            element = selection.next();
            if (feasibility(candidates_list, element)) {
                assign(candidates_list, element);
            }
            if (solution(candidates_list)) {
                return candidates_list;
            }

        }
        return null;

    }
}