SortOperators

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

struct Point {
  int x; int y;
  int Dist2() const { return x * x + y * y;}
//  bool operator<(const Point& right) const { return x < right.x; }
};
Point operator-(const Point& a, const Point& b) { return {a.x - b.x, a.y - b.y}; }

// 1. Оператор <
bool operator<(const Point& left, const Point& right) { return left.x < right.x; }

void BubbleSort1(vector<Point>& v) {
  int n = v.size();
  for (int i = 0; i < n - 1; ++i) {
    for (int j = 0; j < n - 1; ++j) {
      if (v[j + 1] < v[j]) swap(v[j], v[j + 1]);
    }
  }
}

// 2. Функция сравнения
bool CompByDist(const Point& left, const Point& right) {
  return left.Dist2() < right.Dist2();
}

void BubbleSort2(vector<Point>& v, bool (* comp)(const Point&, const Point&)) {
  int n = v.size();
  for (int i = 0; i < n - 1; ++i) {
    for (int j = 0; j < n - 1; ++j) {
      if (comp(v[j + 1], v[j])) swap(v[j], v[j + 1]);
    }
  }
}

// 3. Функтор
struct CompByDistF {
  Point center;
  bool operator()(const Point& left, const Point& right) const {
    return (left - center).Dist2() < (right - center).Dist2();
  }
};

template <class Comp>
void BubbleSort(vector<Point>& v, Comp comp) {
  int n = v.size();
  for (int i = 0; i < n - 1; ++i) {
    for (int j = 0; j < n - 1; ++j) {
      if (comp(v[j + 1], v[j])) swap(v[j], v[j + 1]);
    }
  }
}

int main() {
  vector<Point> v = {{4, 2}, {3, 5}, {1, 9}, {7, 4}, {4, 3}};
  // BubbleSort(v, CompByDist);
//  CompByDistF compf;
//  compf.center = {5, 5};
//  BubbleSort(v, compf);
  Point center = {5, 5};
//  BubbleSort(v, [&center](const Point& left, const Point& right) {
//    return (left - center).Dist2() < (right - center).Dist2();
//  });

  sort(v.begin(), v.end(), [&center](const Point& left, const Point& right) {
    return (left - center).Dist2() < (right - center).Dist2();
  });
  for (auto& p : v)
    cout << p.x << " " << p.y << "\n";
  return 0;
}