leetcode-go/poj/2007.scrambled-polygon/main.cc

#include <algorithm>
#include <cstdio>

using namespace std;

const int N = 50;

struct Vector {
  int x;
  int y;
  Vector(int x = 0, int y = 0) : x(x), y(y) {}
  int operator^(const Vector &that) const {
    return this->x * that.y - that.x * this->y;
  }
  bool operator<(const Vector &that) const { return 0 < ((*this) ^ that); }
} vec[N];

int main() {
  int x, y, n = 0;
  while (scanf("%d %d", &x, &y) != EOF) {
    vec[n].x = x;
    vec[n++].y = y;
  }
  sort(vec + 1, vec + n);
  for (int i = 0; i < n; i++) printf("(%d,%d)\n", vec[i].x, vec[i].y);
  return 0;
}