1041 Be Unique (20)(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
思路:
本题是要找出第一个不重复的数字,用数组来存数字,用map来统计出现的次数。
代码:
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <set>
using namespace std;
map<int, int> m;
int n, a[100005];
int main()
{
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> a[i];
m[a[i]]++;
}
for (int i = 0; i < n; i++)
{
if (m[a[i]] == 1)
{
cout << a[i] << endl;
return 0;
}
}
cout << "None" << endl;
return 0;
}