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, ]. 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 (≤
) 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
解析
找第一个unique的数字。最简单的方法:开一个arr[
]的数字。把每个数字出现的次数+1。
最后就挨个遍历输入的数字:看出现的次数是不是1.
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
using namespace std;
int main()
{
int N;
scanf("%d", &N);
vector<int> data(N,0);
for (int i = 0; i < N; i++)
scanf("%d", &data[i]);
map<int, int> Map;
for (auto x : data)
Map[x]++;
vector<int> Unique;
for (auto x : Map) {
if (x.second == 1)
Unique.push_back(x.first);
}
if (Unique.empty())
printf("None");
else {
for (auto& x : Unique)
x = find(data.cbegin(), data.cend(), x) - data.cbegin();
printf("%d", data[*min_element(Unique.cbegin(), Unique.cend())]);
}
}