PAT A 1041. Be Unique (20)-优快云博客

博客介绍了火星独特的彩票规则，即第一个押注唯一数字者获胜。给出输入输出规格，需记录各编号出现次数，输出第一个出现次数为1的数，还提及使用C++解决PAT相关题目。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

题目

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:

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

记录各个编号的出现次数，输出第一个出现次数为1的数

代码：

#include <iostream>
#include <vector>
using namespace std;

int main()
{
	int n;
	vector<int> data;
	int *flag=new int[100001];	//编号相应数字出现次数标记
	int i;
	for(i=0;i<100001;i++)
		flag[i]=0;

	cin>>n;
	int temp;
	for(i=0;i<n;i++)
	{
		scanf("%d",&temp);
		data.push_back(temp);
		flag[temp]++;
	}
	for(i=0;i<n;i++)
	{
		if(flag[data[i]]==1)
		{
			cout<<data[i];
			return 0;
		}
	}
	cout<<"None";

	return 0;
}