1041. Be Unique (20)

1. 原题： https://www.patest.cn/contests/pat-a-practise/1041

2. 思路：

3. 源码（已AC）：

#include<iostream>
#include<map>
#include<vector>
using namespace std;

int main(void)
{
freopen("in.txt", "r", stdin);
int N;
cin >> N;
vector<int> nv(N);
map<int, int> nmp;

for (int i = 0; i < N; i++)//读入数据
{
cin >> nv[i];
if (nmp.count(nv[i]) == 0)
nmp[nv[i]] = 0;
nmp[nv[i]]++;
}

for (int i = 0; i < N; i++)//遍历vector
{
if (nmp[nv[i]] == 1)
{
cout << nv[i] << endl;
return 0;
}
}
cout << "None\n";

return 0;
}