[PAT] 1041 Be Unique （20 分）Java

Being unique is so important to people on Mars that even their lottery is designed in a unique way. The rule of winning is simple: one bets on a number chosen from [1,10​4​​]. The first one who bets on a unique number wins. For example, if there are 7 people betting on { 5 31 5 88 67 88 17 }, then the second one who bets on 31 wins.

Input Specification:

Each input file contains one test case. Each case contains a line which begins with a positive integer N (≤10​5​​) and then followed by N bets. The numbers are separated by a space.

Output Specification:

For each test case, print the winning number in a line. If there is no winner, print None instead.

Sample Input 1:

7 5 31 5 88 67 88 17

Sample Output 1:

31

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

 1 package pattest;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.IOException;
 5 import java.io.InputStreamReader;
 6 import java.util.ArrayList;
 7 import java.util.List;
 8 
 9 /**
10  * @Auther: Xingzheng Wang
11  * @Date: 2019/2/22 13:51
12  * @Description: pattest
13  * @Version: 1.0
14  */
15 public class PAT1041 {
16     public static void main(String[] args) throws IOException {
17         BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
18         String[] sp = reader.readLine().split(" ");
19 
20         List<String> list1 = new ArrayList<>();
21         List<String> list2 = new ArrayList<>();
22         for (int i = 1; i < sp.length; i++) {
23             if (list1.contains(sp[i])){
24                 list2.add(sp[i]);
25             }else{
26                 list1.add(sp[i]);
27             }
28         }
29         list1.removeAll(list2);
30         if (list1.size() > 0){
31             System.out.print(list1.get(0));
32         }else{
33             System.out.print("None");
34         }
35     }
36 }