「日常训练」The Necklace（UVA-10054）

代码

			for(int i=0; i!=n; ++i)
			{
				int u = cin.nextInt();
				int v = cin.nextInt();
				edges.add(new Edge(u,v));
				startpnt = u;
				if(g.get(u)==null) g.put(u, new ArrayList<Integer> ());
				g.get(u).add(edges.size()-1);
				edges.add(new Edge(v,u));
				if(g.get(v)==null) g.put(v, new ArrayList<Integer> ());
				g.get(v).add(edges.size()-1);
			}
			boolean ok = true;
			for(int i=1;i<=n;++i)
			{
				if(g.get(i)==null) continue;
				if(g.get(i).size()%2==1)
				{
					ok=false;
					break;
				}
			}
			if(ok) euler(startpnt);
			System.out.println("Case #"+kase);
			if(ok && stack.size()==n)
			{
				while(!stack.isEmpty())
				{
					System.out.println(stack.peek().u+" "+stack.peek().v);
					stack.pop();
				}
			}
			else
			{
				System.out.println("some beads may be lost");
			}
			System.out.println();
		}
    }
}