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, 104]. 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 (<=105) 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 17Sample Output 1:
31Sample Input 2:
5 888 666 666 888 888Sample Output 2:
None
1 #include <iostream>
2 #include <set>
3 using namespace std;
4
5 int main(){
6 int n;
7 int i,t;
8 cin>>n;
9 set<int> s,s1;
10 int record[n];
11 cin>>t;
12 s.insert(t);
13 s1.insert(t);
14 record[0] = t;
15 for(i = 1; i < n; i++){
16 cin>>t;
17 record[i] = t;
18 if(s1.find(t) != s1.end() && s.find(t) != s.end()){
19 s.erase(t);
20 }
21 else if(s1.find(t) == s1.end()){
22 s.insert(t);
23 s1.insert(t);
24 }
25
26 }
27 if(s.empty()){
28 cout<<"None";
29 }else{
30 i = 0;
31 while(s.find(record[i]) == s.end()){
32 i++;
33 }
34 cout<<record[i]<<endl;
35 }
36 return 0;
37 }
