地铁路线规划

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刘园 西横堤 1
西横堤 果酒厂 1
果酒厂 本溪路 1
本溪路 勤俭道 1
。。。。。。

public class ComputeShort {
	private Data data; // 存储数据的类
	private EasyCache cache = new EasyCache(); // 缓存数据，防止数据量过大导致内存溢出
	private Path getShortDis(Node a,Node b,Set<Node> visited) {
		// Set里的值是和放入顺序无关的固定顺序,这里恰好可以做cache的key
		String key = a.toString() + b.toString() + visited;
		Path rs = (Path) cache.get(key);
		if (rs != null) {
			//System.out.println("read from cache : " + key);
			return rs;
		}
		// cache里没有则计算
		rs = new Path();
		// 访问过了则返回
		if (visited.contains(a)) {
			cache.put(key,rs);
			return rs;
		} else {
			visited.add(a);
			rs.getPath().add(a);
		}
		// 如果是相连的直接返回结果
		if (a.isConnected(b)) {
			rs.getPath().add(b);
			rs.setDis(data.getDis().get(a,b));
			cache.put(key,rs);
			return rs;
		} else {
			// 否则递归调用
			Iterator<Node> nodes = a.getConnected();
			int tempRs = -1;
			LinkedList<Node> path_temp = null;
			while (nodes.hasNext()) {
				Node temp = nodes.next();
				Integer dis = -1;
				Set<Node> visted_child = new HashSet<Node>();
				visted_child.addAll(visited);
				Path child = getShortDis(temp,b,visted_child);
				if (child.getDis() == -1)
					continue;
				dis = data.getDis().get(a,temp) + child.getDis();
				if (tempRs == -1 || dis < tempRs) {
					tempRs = dis;
					path_temp = child.getPath();
				}
			}
			if (path_temp != null)
				rs.getPath().addAll(path_temp);
			if (tempRs != -1)
				rs.setDis(tempRs);
			cache.put(key,rs);
			return rs;
		}
	}

	public Data getData() {
		return data;
	}

	public void setData(Data data) {
		this.data = data;
	}

	public Path getShort(String a,String b) {
		Node nodeA = data.getNodes().get(a);
		Node nodeB = data.getNodes().get(b);
		Path p = getShortDis(nodeA,nodeB,new HashSet<Node>());
		return p;
	}
	
	public String[] getOneLine(int linename) {
		String[][] line=data.getLine();
		String[] oneLine=new String[line[linename-1].length];
		for(int i = 0;i<line[linename-1].length;i++) {
			oneLine[i]=line[linename-1][i];
		}
		return oneLine;
	}

}