1041. Be Unique (20)

#include <iostream>
#include <vector>

using namespace std;

int flag[10010];

int main()
{
	int n;
	scanf("%d", &n);

	int i, num;
	vector<int> v;

	for(i = 1; i <= n; i++)
	{
		scanf("%d", &num);

		flag[num]++;

		if(flag[num] == 1)
		{
			v.push_back(num);
		}
	}

	int size = v.size(), cur, res = -1;
	for(i = 0; i <= size - 1; i++)
	{
		cur = v[i];
		if(flag[cur] == 1)
		{
			res = cur;
			break;
		}
	}

	if(res == -1)
	{
		printf("None\n");
	}
	else
	{
		printf("%d\n", res);
	}

	system("pause");
	return 0;
}