PAT-1041 Be Unique (20 分)（水题）

1041 Be Unique (20 分)

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

代码

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#include<set>

using namespace std;

const int maxn = 1e5 + 100;
int a[maxn], b[maxn];

int main(){
	int n,t;
	scanf("%d", &n);
    memset(a, 0, sizeof(a));
	for (int i =0; i < n; i++) {
		scanf("%d", &t);
        b[i] = t;
        a[t]++;
	}
    for (int i = 0; i < n; i++) {
        if(a[b[i]] == 1) {
            printf("%d\n", b[i]);
            return 0;
        }
    }
    printf("None\n");
	return 0;
}