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Fill in the following methods:
public interface PointsOnAPlane { /** * Stores a given point in an internal data structure */ void addPoint(Point point); /** * For given ‘center‘ point returns a subset of ‘m‘ stored points that are * closer to the center than others. * * E.g. Stored: (0, 1) (0, 2) (0, 3) (0, 4) (0, 5) * * findNearest(new Point(0, 0), 3) -> (0, 1), (0, 2), (0, 3) */ Collection<Point> findNearest(Point center, int m); }
解法一：用heap和hashmap，space用的好多啊……
HashMap<Points, Double> map; private Comparator<Points> PointsComparator = new Comparator<Points>(){ public int compare(Points A, Points B) { double distA = map.get(A); double distB = map.get(B); if(distA>distB) return 1; else if(distA<distB) return -1; else return 0; } }; @Override public ArrayList<Points> findNearest(Points center, int m) { // TODO Auto-generated method stub map = new HashMap<Points,Double>(); PriorityQueue<Points> q = new PriorityQueue<Points>(m,PointsComparator); for (Points p : points){ double dist = Math.pow((center.getX() - p.getX()),2) + Math.pow((center.getY() - p.getY()),2) ; map.put(p,dist); q.add(p); } ArrayList<Points> nearestPoints = new ArrayList<Points>(); for (int i = 0; i < m; i++){ nearestPoints.add(q.poll()); } return nearestPoints; }
完整版本见eclipse……
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原文地址：http://www.cnblogs.com/hygeia/p/5154490.html
