Symmetry

Symmetry

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

int main()
{
    int t=0,n=0,x=0,y=0;
    cin >> t;
    for (int i = 0; i < t; i++)
    {
        multimap<int, int> coordinate;//关键字可重复的map
        cin >> n;
        for (int j = 0; j < n; j++)
        {
            cin >> x >> y;
            coordinate.insert(pair<int, int>(x, y));
        }
        auto map_it = coordinate.cend();//const_iterator迭代器。这个迭代器是可以自己增加的，但是其所指向的元素是不可以被改变的。
        map_it--;
        float mid =(float) (coordinate.cbegin()->first + map_it->first) / 2;
        map_it = coordinate.cbegin();
        int sign = 0;
        for (int j = 0; j < n; j++)
            sign += (map_it++)->first;
        if ((float)sign == mid*n)
            cout << "YES\n";
        else
            cout << "NO\n";
    }
    system("pause");
    return 0;
}

运行结果：

运行结果