PAT (Advanced Level) Practise 1041 Be Unique (20)

1041. Be Unique (20)

时间限制

100 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

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 17

Sample Output 1:

31

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

输出最先出现的只出现一次的数，直接统计每个数的出现次数就好了

#include<cstdio>    #include<cstring>    #include<cmath>    #include<algorithm>    #include<queue>    using namespace std;typedef long long ll;const int maxn = 1e5 + 5;int f[maxn], n, a[maxn];int main(){scanf("%d", &n);for (int i = 0; i < n; i++) scanf("%d", &a[i]), f[a[i]]++;for (int i = 0; i < n; i++){if (f[a[i]] == 1) { printf("%d\n", a[i]); return 0; }}printf("None\n");return 0;}