PAT A1041

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

注意数组范围，最后两个测试点的数目很大，如果4,5测试点出错可能数组设置较小，否则得分16分

    #include
    #include
    #include
    #include
    #include
    #include
    
    
    using namespace std;
    
    int  hashTable[10001]={0},num[1000001]={0};
    
    int main(){
    	int n;
    	cin>>n;
    
    	int count=0;
    	while(n){
    		scanf("%d",&num[count]);
    		hashTable[num[count]]++;
    		count++;
    		n--;
    	}	
    for(int i=0;i<count;i++){
    	
    	if(hashTable[num[i]]==1)
    	{
    		cout<<num[i];
    		break;
    	}
    	if(i==count-1)
    	printf("None");
    }
    	
    	return 0;
    }