CCF之送货（java）

解题代码（java）：

import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;
import java.util.Vector;
public class Main {

public static Vector<Integer> []G = new Vector[10010];
public static int []d = new int[10010];
public static boolean [][]edge = new boolean [10010][10010];
public static Stack<Integer> S = new Stack<Integer>();
public static Queue<Integer> q = new LinkedList<Integer>();

static int bfs(int s,int n){

boolean []vis = new boolean[10010];
q.add(s);
vis[s]=true;
while(!q.isEmpty()){
int u=q.remove();

for(int i=0;i<G[u].size();++i){
int v=G[u].get(i);
if(!vis[v]){
vis[v]=true;
q.add(v);
}

}
}
int x = 0;
for(int i = 1;i<n+1;i++)
{
if(!vis[i])
{
x++;
}

}
return x;
}

private static void DFS1(int u,int n) {

for(int i=0;i<G[u].size();++i){
int v=G[u].get(i);
if(!edge[u][v]){
edge[u][v]=edge[v][u] =true;
DFS1(v,n);
S.push(v);
}

}
}

static class comp implements Comparator<Integer>
{

@Override
public int compare(Integer o1, Integer o2) {
// TODO Auto-generated method stub
return o1-o2;
}

}

public static void main(String[] args) {

Scanner in = new Scanner(System.in);
int n = in.nextInt();
int m = in.nextInt();

for(int i = 0;i<n+1;i++)
{
G[i] = new Vector<Integer>();

}

for(int i = 1;i<m+1;i++)
{

int x = in.nextInt();
int y = in.nextInt();
G[x].add(y);
G[y].add(x);
d[x]++;
d[y]++;

}
in.close();

int number = 0;

for (int i=1;i<n+1;i++)
{
if (d[i]%2!=0)
number++;
}

if (bfs(1,n)==0 && (number==0 ||number==2))
{
for(int i = 1;i<n+1;i++)
{
Collections.sort(G[i]);

}

DFS1(1,n);
System.out.print(1);
while(!S.empty())
{
System.out.print(" "+S.pop());
}

}
else
System.out.println(-1);

}

} 运行超时，算法没学好，希望大神帮忙，50分