T2

#include <vector>
#include <iostream>
#include <string>
#include <c++/algorithm>
#include <c++/map>
using namespace std;
struct Coord{
    int x;
    int y;
};

vector<Coord> kClosest(vector<Coord>& points, Coord e, int K) {
    vector<Coord> res;
    map<int,Coord,less_equal<int>> m;
    for(int i=0;i<points.size();i++){

        int dis=pow((points[i].x-e.x),2)+pow((points[i].y-e.y),2);   //KEY为距离，VALUE为坐标
        m[dis]=points[i];
    }
    for (auto it = m.begin(); it != m.end(); ++it) {
        if (K==0)
            break;
        K--;
        res.push_back(it->second);
    }
    return res;
}
int main(){
    Coord e ={0,0};
    Coord p1 ={2,3};
    Coord p2 ={4,5};
    Coord p3 ={1,1};
    Coord p4 ={-1,-1};
    vector<Coord> points;
    points.push_back(p1);
    points.push_back(p2);
    points.push_back(p3);
    points.push_back(p4);
    const vector<Coord> &vector = kClosest(points, e, 2);
    for (int i = 0; i < vector.size(); ++i) {
        cout<<vector[i].x<<" "<<vector[i].y<<endl;
    }
    return 0;
}