package util.graph;

import java.util.HashSet;
import java.util.PriorityQueue;
import java.util.Set;

public class DynDjikstra {
    public static State FindShortest(Node start, Node target) {
        PriorityQueue<Node> openSet = new PriorityQueue<>();
        Set<Node> closedSet = new HashSet<>();
        openSet.add(start);
        while (!openSet.isEmpty()) {
            Node current = openSet.poll();
            for (Edge edge : current.edges) {
                Node end = edge.target;
                if (closedSet.contains(end)) {
                    continue;
                }
                State newState = edge.travel(current.last);
                //if (end.equals(target)) {
                    //return newState;
                //}
                if (openSet.contains(end)) {
                    if (end.last.compareTo(newState)>0) {
                        end.last = newState;
                    }
                } else {
                    openSet.add(end);
                    end.last = newState;
                }
            }
            closedSet.add(current);
            if (closedSet.contains(target)) {
                return target.last;
            }
        }

        return target.last;
    }
}

package fixjava;

import java.util.ArrayList;
import java.util.List;

public class Take<T> {

	/** Return at most n items from the beginning of the Iterable. */
	public static <T> ArrayList<T> head(Iterable<T> collection, int n) {
		ArrayList<T> head = new ArrayList<T>();
		int count = n;
		if (n > 0)
			for (T item : collection) {
				head.add(item);
				if (--count == 0)
					break;
			}
		return head;
	}

	/** Return at most n items from the end of the List. */
	public static <T> ArrayList<T> tail(List<T> list, int n) {
		ArrayList<T> tail = new ArrayList<T>();
		for (int len = list.size(), i = Math.max(len - n, 0); i < len; i++)
			tail.add(list.get(i));
		return tail;
	}

}
