题解 | 牛牛的考试

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
using PIC=pair<int,char>;

int main()
{
    int T;cin>>T;
    cin.ignore();
    for(int i=0;i<T;i++)
    {
        vector<PIC> options;
        string a,b,c,d;
        getline(cin,a);
        getline(cin,b);
        getline(cin,c);
        getline(cin,d);
        options.push_back({a.size(),'A'});
        options.push_back({b.size(),'B'});
        options.push_back({c.size(),'C'});
        options.push_back({d.size(),'D'});
        sort(options.begin(),options.end());

        int val_min=options[0].first;
        int val_max=options[3].first;

        int count_min=0,count_max=0;
        for(const auto& p:options)
        {
            if(p.first==val_min)
            {
                count_min++;
            }
            if(p.first==val_max)
            {
                count_max++;
            }
        }

        bool has_unique_short=(count_min==1);
        bool has_unique_long=(count_max==1);

        if(has_unique_short&&!has_unique_long)
        {
            cout<<options[0].second<<endl;
        }
        else if(!has_unique_short&&has_unique_long)
        {
            cout<<options[3].second<<endl;
        }
        else 
        {
            cout<<'C'<<endl;
        }
    }
    return 0;
}