三个超时
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// write your code here
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
String[][] str=new String[n][2];
int i,j,k;
for (i=0;i<n;i++){
str[i][0]=sc.next();
str[i][1]=sc.next();
}
int m=sc.nextInt();
ArrayList<String> total=new ArrayList<String>();
for (j=0;j<m;j++){
total.add(sc.next());
}
//输入完成,接下来是对比
for (i=0;i<n;i++){
for (j=0;j<total.size();j++){
if (str[i][0].equals(total.get(j))){
for (k=0;k<total.size();k++){
if (str[i][1].equals(total.get(k))){
total.remove(j);
total.remove(k);
}
}
}
}
}
System.out.println(total.size());
//接下来要对total中的字符串元素进行排序
Object[] o=total.toArray();
int[] arr=new int[o.length];
for (i=0;i<arr.length;i++){
arr[i]=Integer.parseInt(o[i]+"");
}
Arrays.sort(arr);
int x=-1;
for (i=0;i<arr.length;i++){
for (j=0;j<total.size();j++){
if (arr[i]==Integer.parseInt(total.get(j))){
if (i==arr.length-1){
System.out.print(total.get(j));
}else
System.out.print(total.get(j)+" ");
};
}
}
}
}