PAT--甲 1041 Be Unique

甲 1041 Be Unique (题解)

1041 Be Unique (题解)

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 [1,1000 ]. 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.

输入格式:

Each input file contains one test case. Each case contains a line which begins with a positive integer N (≤10000 ) and then followed by N bets. The numbers are separated by a space.

输出格式:

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

输入样例1:

7 5 31 5 88 67 88 17

输出样例1:

31

输入样例2:

5 888 666 666 888 888

输出样例2:

None

思路:

追个接收数字，用哈希数组进行计数，如果该数字第一次出现，则将该树存储在b中，则b中存储的为出现过的数字，再利用数组b进行判断，如果第一次出现且只出现一次，则输出该树，如果没有符合范围的则输出”None”。

我的代码如下:

#include <stdio.h>
int main()
{
	int N,count=0;
	scanf("%d",&N); 
	int a[10010]={0};
	int b[10010]={0};
	for(int i=0;i<N;i++)
	{
		int m;
		scanf("%d",&m);	\\输入m，并记录次数
		a[m]++;
		if(a[m]==1)		\\如果是第一次，该数字第一次出现，将该数字存储在b中
		b[count++]=m;
	}
	int j;
	for(j=0;j<count;j++)
		if(a[b[j]]==1)
		{
			printf("%d\n",b[j]);
			break;
		}
	if(j==count)
		printf("None\n");
	return 0;
}