CCW Algorithm Implementation

ccw.cpp

#include <bits/stdc++.h>
using namespace std;

// [COPY START]
struct Point {
  long long x, y;
};

enum Orientation { CW = -1, COLLINEAR = 0, CCW = 1 };

long long ccw(const Point& a, const Point& b, const Point& c) {
  return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
}

Orientation orientation(const Point& a, const Point& b, const Point& c) {
  long long v = ccw(a, b, c);
  if (v > 0) return CCW;
  if (v < 0) return CW;
  return COLLINEAR;
}
// [COPY END]

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  Point a, b, c;
  if (!(cin >> a.x >> a.y >> b.x >> b.y >> c.x >> c.y)) return 0;

  auto r = orientation(a, b, c);
  if (r == CCW)
    cout << "CCW\n";
  else if (r == CW)
    cout << "CW\n";
  else
    cout << "COLLINEAR\n";
}