Problem p00857 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

#define EPS (1e-7)
#define equals(a, b) (fabs((a) - (b)) < EPS)
#define COUNTER_CLOCKWISE 1
#define CLOCKWISE -1
#define ONLINE_BACK 2
#define ONLINE_FRONT -2
#define ON_SEGMENT 0
#define REP(i, s, n) for (int i = s; i < n; i++)
#define rep(i, n) REP(i, 0, n)

using namespace std;

class Point {
public:
  double x, y;

  Point(double x = 0, double y = 0) : x(x), y(y) {}

  Point operator+(Point p) { return Point(x + p.x, y + p.y); }
  Point operator-(Point p) { return Point(x - p.x, y - p.y); }
  Point operator*(double a) { return Point(a * x, a * y); }
  Point operator/(double a) { return Point(x / a, y / a); }
  Point operator*(Point a) {
    return Point(x * a.x - y * a.y, x * a.y + y * a.x);
  }

  bool operator<(const Point &p) const {
    return !equals(x, p.x) ? x < p.x : (!equals(y, p.y) && y < p.y);
  }

  bool operator==(const Point &p) const {
    return fabs(x - p.x) < EPS && fabs(y - p.y) < EPS;
  }
};

struct Segment {
  Point p1, p2;
  Segment(Point p1 = Point(), Point p2 = Point()) : p1(p1), p2(p2) {}
  bool operator<(const Segment &s) const {
    return (p2 == s.p2) ? p1 < s.p1 : p2 < s.p2;
  }
  bool operator==(const Segment &s) const {
    return (s.p1 == p1 && s.p2 == p2) || (s.p1 == p2 && s.p2 == p1);
  }
};

typedef Point Vector;
typedef Segment Line;
typedef vector<Point> Polygon;

ostream &operator<<(ostream &os, const Point &a) {
  os << "(" << a.x << "," << a.y << ")";
}

ostream &operator<<(ostream &os, const Segment &a) {
  os << "( " << a.p1 << " , " << a.p2 << " )";
}

double dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }

double cross(Point a, Point b) { return a.x * b.y - a.y * b.x; }

double norm(Point a) { return a.x * a.x + a.y * a.y; }

double abs(Point a) { return sqrt(norm(a)); }

// rad ????§???????????????¢?????§?????????????????¨
Point rotate(Point a, double rad) {
  return Point(cos(rad) * a.x - sin(rad) * a.y,
               sin(rad) * a.x + cos(rad) * a.y);
}

// ??????????????¢????????????
double toRad(double agl) { return agl * M_PI / 180.0; }

int ccw(Point p0, Point p1, Point p2) {
  Point a = p1 - p0;
  Point b = p2 - p0;
  if (cross(a, b) > EPS)
    return COUNTER_CLOCKWISE;
  if (cross(a, b) < -EPS)
    return CLOCKWISE;
  if (dot(a, b) < -EPS)
    return ONLINE_BACK;
  if (norm(a) < norm(b))
    return ONLINE_FRONT;
  return ON_SEGMENT;
}

bool intersectLL(Line l, Line m) {
  return abs(cross(l.p2 - l.p1, m.p2 - m.p1)) > EPS || // non-parallel
         abs(cross(l.p2 - l.p1, m.p1 - l.p1)) < EPS;   // same line
}
bool intersectLS(Line l, Line s) {
  return cross(l.p2 - l.p1, s.p1 - l.p1) * // s[0] is left of l
             cross(l.p2 - l.p1, s.p2 - l.p1) <
         EPS; // s[1] is right of l
}
bool intersectLP(Line l, Point p) {
  return abs(cross(l.p2 - p, l.p1 - p)) < EPS;
}
bool intersectSS(Line s, Line t) {
  return ccw(s.p1, s.p2, t.p1) * ccw(s.p1, s.p2, t.p2) <= 0 &&
         ccw(t.p1, t.p2, s.p1) * ccw(t.p1, t.p2, s.p2) <= 0;
}
bool intersectSP(Line s, Point p) {
  return abs(s.p1 - p) + abs(s.p2 - p) - abs(s.p2 - s.p1) <
         EPS; // triangle inequality
}

Point projection(Line l, Point p) {
  double t = dot(p - l.p1, l.p1 - l.p2) / norm(l.p1 - l.p2);
  return l.p1 + (l.p1 - l.p2) * t;
}
Point reflection(Line l, Point p) { return p + (projection(l, p) - p) * 2; }
double distanceLP(Line l, Point p) { return abs(p - projection(l, p)); }
double distanceLL(Line l, Line m) {
  return intersectLL(l, m) ? 0 : distanceLP(l, m.p1);
}

double distanceLS(Line l, Line s) {
  if (intersectLS(l, s))
    return 0;
  return min(distanceLP(l, s.p1), distanceLP(l, s.p2));
}
double distanceSP(Line s, Point p) {
  Point r = projection(s, p);
  if (intersectSP(s, r))
    return abs(r - p);
  return min(abs(s.p1 - p), abs(s.p2 - p));
}

double distanceSS(Line s, Line t) {
  if (intersectSS(s, t))
    return 0;
  return min(min(distanceSP(s, t.p1), distanceSP(s, t.p2)),
             min(distanceSP(t, s.p1), distanceSP(t, s.p2)));
}

Point crosspoint(Line l, Line m) {
  double A = cross(l.p2 - l.p1, m.p2 - m.p1);
  double B = cross(l.p2 - l.p1, l.p2 - m.p1);
  if (abs(A) < EPS && abs(B) < EPS) {
    vector<Point> vec;
    vec.push_back(l.p1), vec.push_back(l.p2), vec.push_back(m.p1),
        vec.push_back(m.p2);
    sort(vec.begin(), vec.end());
    assert(vec[1] == vec[2]); //???????????°??????????????????
    return vec[1];
    // return m.p1;
  }
  if (abs(A) < EPS)
    assert(false);
  return m.p1 + (m.p2 - m.p1) * (B / A);
}

// cross product of pq and pr
double cross3p(Point p, Point q, Point r) {
  return (r.x - q.x) * (p.y - q.y) - (r.y - q.y) * (p.x - q.x);
}

// returns true if point r is on the same line as the line pq
bool collinear(Point p, Point q, Point r) {
  return fabs(cross3p(p, q, r)) < EPS;
}

// returns true if point t is on the left side of line pq
bool ccwtest(Point p, Point q, Point r) {
  return cross3p(p, q, r) > 0; // can be modified to accept collinear points
}

bool onSegment(Point p, Point q, Point r) {
  return collinear(p, q, r) &&
         equals(sqrt(pow(p.x - r.x, 2) + pow(p.y - r.y, 2)) +
                    sqrt(pow(r.x - q.x, 2) + pow(r.y - q.y, 2)),
                sqrt(pow(p.x - q.x, 2) + pow(p.y - q.y, 2)));
}

double angle(Point a, Point b, Point c) {
  double ux = b.x - a.x, uy = b.y - a.y;
  double vx = c.x - a.x, vy = c.y - a.y;
  return acos((ux * vx + uy * vy) /
              sqrt((ux * ux + uy * uy) * (vx * vx + vy * vy)));
}

//????§???¢poly?????????????????????????????????p????????¨??????????????????????????????
bool inPolygon(Polygon &poly, Point p, bool onseg = true) {
  if ((int)poly.size() == 0)
    return false;
  if (onseg)
    rep(i, (int)poly.size()) if (onSegment(poly[i],
                                           poly[(i + 1) % (int)poly.size()],
                                           p)) return true;
  double sum = 0;
  for (int i = 0; i < (int)poly.size(); i++) {
    if (equals(cross(poly[i] - p, poly[(i + 1) % poly.size()] - p), 0.0))
      continue; // ????????????????????¨angle???nan?????????sum???nan??????????????¬
    if (cross3p(p, poly[i], poly[(i + 1) % poly.size()]) < 0)
      sum -= angle(p, poly[i], poly[(i + 1) % poly.size()]);
    else
      sum += angle(p, poly[i], poly[(i + 1) % poly.size()]);
  }
  // ?????????????????????????????????????????¨?????????????????§??\\?????????????????????
  const double eps = 1e-5;
  return (fabs(sum - 2 * M_PI) < eps || fabs(sum + 2 * M_PI) < eps);
}

pair<Point, Point> crosspointCC(Point C1, double r1, Point C2, double r2) {
  complex<double> c1(C1.x, C1.y);
  complex<double> c2(C2.x, C2.y);
  complex<double> A = conj(c2 - c1),
                  B = (r2 * r2 - r1 * r1 - (c2 - c1) * conj(c2 - c1)),
                  C = r1 * r1 * (c2 - c1);
  complex<double> D = B * B - 4.0 * A * C;
  complex<double> z1 = (-B + sqrt(D)) / (2.0 * A) + c1,
                  z2 = (-B - sqrt(D)) / (2.0 * A) + c1;
  return pair<Point, Point>(Point(z1.real(), z1.imag()),
                            Point(z2.real(), z2.imag()));
}

// ------

bool LT(double a, double b) { return !equals(a, b) && a < b; }
bool LTE(double a, double b) { return equals(a, b) || a < b; }

bool isValid(Point p) {
  return LTE(-100.0, p.x) && LTE(p.x, 100.0) && LTE(-100.0, p.y) &&
         LTE(p.y, 100.0);
}

vector<Point> base(3), ps(3);

Point vir;
bool cmp_dist(const Point &p1, const Point &p2) {
  return LT(abs(vir - p1), abs(vir - p2));
}

// seg.p1 ??? base ?????????????????§???????????¨
// * 6
bool checkIntersect(Point p, Segment seg1, Segment seg2) {

  // baseSeg ??¨ seg1 ????????? seg2
  // ??????????????¨?????°???????????????????§???¢???????????????
  rep(i, 3) {
    Segment baseSeg = Segment(base[i], base[(i + 1) % 3]);
    if (equals(cross(baseSeg.p1 - baseSeg.p2, seg1.p1 - seg1.p2), 0) &&
        equals(cross(baseSeg.p1 - baseSeg.p2, seg2.p1 - seg2.p2), 0))
      return false;
  }

  // ?????§???????????´???????????§?????????????????§???????????§????????????????????????????§???¢??¨??????????????????????????§????????????
  Segment segs[2] = {seg1, seg2};
  rep(i, 2) {
    Segment seg = segs[i];
    rep(j, 3) {
      Segment baseSeg = Segment(base[j], base[(j + 1) % 3]);
      if (intersectSS(seg, baseSeg)) {
        if (equals(cross(seg.p1 - seg.p2, baseSeg.p1 - baseSeg.p2), 0)) {
          // if( equals(cross(seg.p1-seg.p2,baseSeg.p1-baseSeg.p2),0) && seg.p1
          // == baseSeg.p1 ) { int res = ccw(seg.p1,seg.p2,baseSeg.p2); if( res
          // == ONLINE_FRONT || res == ON_SEGMENT ) return false;

          vector<Point> vec;
          vec.push_back(seg.p1);
          vec.push_back(seg.p2);
          vec.push_back(baseSeg.p1);
          vec.push_back(baseSeg.p2);
          sort(vec.begin(), vec.end());
          // vir = vec[0];
          // sort(vec.begin(),vec.end(),cmp_dist);
          vec.erase(unique(vec.begin(), vec.end()), vec.end());
          rep(i, (int)vec.size() - 1) {
            Point mp = (vec[i] + vec[i + 1]) / 2.0;
            if (onSegment(seg.p1, seg.p2, mp) &&
                onSegment(baseSeg.p1, baseSeg.p2, mp))
              return false;
          }

          continue;
        }
        Point cp = crosspoint(seg, baseSeg);
        if (!(cp == seg.p1))
          return false;
      }
    }
  }

  return true;
}

inline bool check(Point p, int j) {
  // ??????????????????????????????p????????¨?????????
  if (!isValid(p))
    return false;

  // ????????????????§???¢??¨?????????????????????????§?????????°????????????

  // ????????????????§???¢???????????\\?§????????????????????????????
  // if( inPolygon(base,p,true) ) return false;
  // return !inPolygon(base,p,true);
  double cs[3];

  rep(i, 3) {
    if (onSegment(base[i], base[(i + 1) % 3], p))
      return false;
    Point a = base[(i + 1) % 3] - base[i];
    Point b = p - base[i];
    cs[i] = cross(a, b);
  }
  if (LT(cs[0], 0) && LT(cs[1], 0) && LT(cs[2], 0))
    return false;
  if (LT(0, cs[0]) && LT(0, cs[1]) && LT(0, cs[2]))
    return false;

  if (!checkIntersect(p, Segment(base[j], p), Segment(base[(j + 1) % 3], p)))
    return false;

  return true;
  // return checkIntersect(p,Segment(base[i],p),Segment(base[(i+1)%3],p));
}

//???????????????????????????????????????????????????????????????????????§??????
bool FinalCheck(int limit = 3) {
  Line lines[3][2];
  rep(i, limit) lines[i][0] = Line(base[i], ps[i]),
                lines[i][1] = Line(base[(i + 1) % 3], ps[i]);
  rep(i, limit) {
    REP(j, i + 1, limit) {
      if (ps[i] == ps[j])
        return false;
      rep(k, 2) {
        Segment ururu_beam1 = lines[i][k];
        rep(l, 2) {
          Segment ururu_beam2 = lines[j][l];
          if (intersectSS(ururu_beam1, ururu_beam2)) {
            Point cp = crosspoint(ururu_beam1, ururu_beam2);
            if (cp == ururu_beam1.p1 && cp == ururu_beam2.p1)
              continue;
            return false;
          }
        }
      }
    }
  }
  return true;
}

double getH() {

  Line lines[3];
  rep(i, 3) {
    Vector e = (base[i] - base[(i + 1) % 3]) / abs(base[i] - base[(i + 1) % 3]);
    e = rotate(e, toRad(90.0));
    lines[i] = Line(ps[i], ps[i] + e * 1000);
  }

  Point cp = crosspoint(lines[0], lines[1]);
  rep(i, 3) if (cp == ps[i]) return 1e30;

  Point onBaseP0 = crosspoint(lines[0], Line(base[0], base[1]));

  double a = abs(cp - onBaseP0);
  double b = abs(onBaseP0 - ps[0]);
  if (equals(a, b))
    return 1e30;
  if (LTE(b, a))
    return 1e30;

  return sqrt(b * b - a * a);
}

void compute() {
  double mini = 1e30;
  REP(x1, -100, 101) {
    REP(y1, -100, 101) {
      if (y1 == -21 || y1 == 66)
        continue;
      if (!check(Point(x1, y1), 0))
        continue;
      ps[0] = Point(x1, y1);
      double lengthOfPs0ToBase1 = abs(ps[0] - base[1]);
      // REP(x2,-100,101){
      for (int x2 = max(-100, (int)(base[1].x - lengthOfPs0ToBase1));
           x2 <= min(100, (int)(base[1].x + lengthOfPs0ToBase1)); x2++) {
        double diff_x = abs(x2 - base[1].x);
        if (LT(lengthOfPs0ToBase1, diff_x))
          continue;
        double diff_y =
            sqrt(lengthOfPs0ToBase1 * lengthOfPs0ToBase1 - diff_x * diff_x);

        if (!equals(diff_y, (int)(diff_y + EPS)))
          continue;
        for (int coef = -1; coef <= 1; coef += 2) { // ????£????????????????
          double y2 = base[1].y + diff_y * (double)coef;
          if (!(equals(y2, (int)(y2 + EPS)) || equals(y2, (int)(y2 - EPS))))
            continue;
          if (!check(Point(x2, y2), 1))
            continue;
          ps[1] = Point(x2, y2);
          if (!FinalCheck(2))
            continue;
          pair<Point, Point> tmp = crosspointCC(base[0], abs(ps[0] - base[0]),
                                                base[2], abs(ps[1] - base[2]));
          Point tps[2] = {tmp.first, tmp.second};
          bool succ = false;
          rep(i, 2) {
            if (!check(tps[i], 2))
              continue;
            ps[2] = tps[i];

            if (!(equals(ps[2].x, (int)(ps[2].x + EPS)) ||
                  equals(ps[2].x, (int)(ps[2].x - EPS))) ||
                !(equals(ps[2].y, (int)(ps[2].y + EPS)) ||
                  equals(ps[2].y, (int)(ps[2].y - EPS))))
              continue;
            if (!FinalCheck())
              continue;
            double h = getH();
            if (LT(h, mini))
              mini = h;
            if (!equals(h, 1e30)) {
              succ = true;
              break;
            }
          }
          if (succ)
            break;
        }
      }
    }
  }
  if (equals(mini, 1e30))
    puts("-1");
  else
    printf("%.10f\\n", mini);
}

int main() {
  while (1) {
    bool fin = true;
    rep(i, 3) {
      scanf("%lf %lf", &base[i].x, &base[i].y);
      if (!(base[i] == Point(0, 0)))
        fin = false;
    }
    if (fin)
      break;
    compute();
  }
  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>

#define EPS (1e-7)
#define equals(a, b) (fabs((a) - (b)) < EPS)
#define COUNTER_CLOCKWISE 1
#define CLOCKWISE -1
#define ONLINE_BACK 2
#define ONLINE_FRONT -2
#define ON_SEGMENT 0
#define REP(i, s, n) for (int i = s; i < n; i++)
#define rep(i, n) REP(i, 0, n)

using namespace std;

class Point {
public:
  double x, y;

  Point(double x = 0, double y = 0) : x(x), y(y) {}

  Point operator+(Point p) { return Point(x + p.x, y + p.y); }
  Point operator-(Point p) { return Point(x - p.x, y - p.y); }
  Point operator*(double a) { return Point(a * x, a * y); }
  Point operator/(double a) { return Point(x / a, y / a); }
  Point operator*(Point a) {
    return Point(x * a.x - y * a.y, x * a.y + y * a.x);
  }

  bool operator<(const Point &p) const {
    return !equals(x, p.x) ? x < p.x : (!equals(y, p.y) && y < p.y);
  }

  bool operator==(const Point &p) const {
    return fabs(x - p.x) < EPS && fabs(y - p.y) < EPS;
  }
};

struct Segment {
  Point p1, p2;
  Segment(Point p1 = Point(), Point p2 = Point()) : p1(p1), p2(p2) {}
  bool operator<(const Segment &s) const {
    return (p2 == s.p2) ? p1 < s.p1 : p2 < s.p2;
  }
  bool operator==(const Segment &s) const {
    return (s.p1 == p1 && s.p2 == p2) || (s.p1 == p2 && s.p2 == p1);
  }
};

typedef Point Vector;
typedef Segment Line;
typedef vector<Point> Polygon;

ostream &operator<<(ostream &os, const Point &a) {
  os << "(" << a.x << "," << a.y << ")";
}

ostream &operator<<(ostream &os, const Segment &a) {
  os << "( " << a.p1 << " , " << a.p2 << " )";
}

double dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }

double cross(Point a, Point b) { return a.x * b.y - a.y * b.x; }

double norm(Point a) { return a.x * a.x + a.y * a.y; }

double abs(Point a) { return sqrt(norm(a)); }

// rad ????§???????????????¢?????§?????????????????¨
Point rotate(Point a, double rad) {
  return Point(cos(rad) * a.x - sin(rad) * a.y,
               sin(rad) * a.x + cos(rad) * a.y);
}

// ??????????????¢????????????
double toRad(double agl) { return agl * M_PI / 180.0; }

int ccw(Point p0, Point p1, Point p2) {
  Point a = p1 - p0;
  Point b = p2 - p0;
  if (cross(a, b) > EPS)
    return COUNTER_CLOCKWISE;
  if (cross(a, b) < -EPS)
    return CLOCKWISE;
  if (dot(a, b) < -EPS)
    return ONLINE_BACK;
  if (norm(a) < norm(b))
    return ONLINE_FRONT;
  return ON_SEGMENT;
}

bool intersectLL(Line l, Line m) {
  return abs(cross(l.p2 - l.p1, m.p2 - m.p1)) > EPS || // non-parallel
         abs(cross(l.p2 - l.p1, m.p1 - l.p1)) < EPS;   // same line
}
bool intersectLS(Line l, Line s) {
  return cross(l.p2 - l.p1, s.p1 - l.p1) * // s[0] is left of l
             cross(l.p2 - l.p1, s.p2 - l.p1) <
         EPS; // s[1] is right of l
}
bool intersectLP(Line l, Point p) {
  return abs(cross(l.p2 - p, l.p1 - p)) < EPS;
}
bool intersectSS(Line s, Line t) {
  return ccw(s.p1, s.p2, t.p1) * ccw(s.p1, s.p2, t.p2) <= 0 &&
         ccw(t.p1, t.p2, s.p1) * ccw(t.p1, t.p2, s.p2) <= 0;
}
bool intersectSP(Line s, Point p) {
  return abs(s.p1 - p) + abs(s.p2 - p) - abs(s.p2 - s.p1) <
         EPS; // triangle inequality
}

Point projection(Line l, Point p) {
  double t = dot(p - l.p1, l.p1 - l.p2) / norm(l.p1 - l.p2);
  return l.p1 + (l.p1 - l.p2) * t;
}
Point reflection(Line l, Point p) { return p + (projection(l, p) - p) * 2; }
double distanceLP(Line l, Point p) { return abs(p - projection(l, p)); }
double distanceLL(Line l, Line m) {
  return intersectLL(l, m) ? 0 : distanceLP(l, m.p1);
}

double distanceLS(Line l, Line s) {
  if (intersectLS(l, s))
    return 0;
  return min(distanceLP(l, s.p1), distanceLP(l, s.p2));
}
double distanceSP(Line s, Point p) {
  Point r = projection(s, p);
  if (intersectSP(s, r))
    return abs(r - p);
  return min(abs(s.p1 - p), abs(s.p2 - p));
}

double distanceSS(Line s, Line t) {
  if (intersectSS(s, t))
    return 0;
  return min(min(distanceSP(s, t.p1), distanceSP(s, t.p2)),
             min(distanceSP(t, s.p1), distanceSP(t, s.p2)));
}

Point crosspoint(Line l, Line m) {
  double A = cross(l.p2 - l.p1, m.p2 - m.p1);
  double B = cross(l.p2 - l.p1, l.p2 - m.p1);
  if (abs(A) < EPS && abs(B) < EPS) {
    vector<Point> vec;
    vec.push_back(l.p1), vec.push_back(l.p2), vec.push_back(m.p1),
        vec.push_back(m.p2);
    sort(vec.begin(), vec.end());
    assert(vec[1] == vec[2]); //???????????°??????????????????
    return vec[1];
    // return m.p1;
  }
  if (abs(A) < EPS)
    assert(false);
  return m.p1 + (m.p2 - m.p1) * (B / A);
}

// cross product of pq and pr
double cross3p(Point p, Point q, Point r) {
  return (r.x - q.x) * (p.y - q.y) - (r.y - q.y) * (p.x - q.x);
}

// returns true if point r is on the same line as the line pq
bool collinear(Point p, Point q, Point r) {
  return fabs(cross3p(p, q, r)) < EPS;
}

// returns true if point t is on the left side of line pq
bool ccwtest(Point p, Point q, Point r) {
  return cross3p(p, q, r) > 0; // can be modified to accept collinear points
}

bool onSegment(Point p, Point q, Point r) {
  return collinear(p, q, r) &&
         equals(sqrt(pow(p.x - r.x, 2) + pow(p.y - r.y, 2)) +
                    sqrt(pow(r.x - q.x, 2) + pow(r.y - q.y, 2)),
                sqrt(pow(p.x - q.x, 2) + pow(p.y - q.y, 2)));
}

double angle(Point a, Point b, Point c) {
  double ux = b.x - a.x, uy = b.y - a.y;
  double vx = c.x - a.x, vy = c.y - a.y;
  return acos((ux * vx + uy * vy) /
              sqrt((ux * ux + uy * uy) * (vx * vx + vy * vy)));
}

//????§???¢poly?????????????????????????????????p????????¨??????????????????????????????
bool inPolygon(Polygon &poly, Point p, bool onseg = true) {
  if ((int)poly.size() == 0)
    return false;
  if (onseg)
    rep(i, (int)poly.size()) if (onSegment(poly[i],
                                           poly[(i + 1) % (int)poly.size()],
                                           p)) return true;
  double sum = 0;
  for (int i = 0; i < (int)poly.size(); i++) {
    if (equals(cross(poly[i] - p, poly[(i + 1) % poly.size()] - p), 0.0))
      continue; // ????????????????????¨angle???nan?????????sum???nan??????????????¬
    if (cross3p(p, poly[i], poly[(i + 1) % poly.size()]) < 0)
      sum -= angle(p, poly[i], poly[(i + 1) % poly.size()]);
    else
      sum += angle(p, poly[i], poly[(i + 1) % poly.size()]);
  }
  // ?????????????????????????????????????????¨?????????????????§??\\?????????????????????
  const double eps = 1e-5;
  return (fabs(sum - 2 * M_PI) < eps || fabs(sum + 2 * M_PI) < eps);
}

pair<Point, Point> crosspointCC(Point C1, double r1, Point C2, double r2) {
  complex<double> c1(C1.x, C1.y);
  complex<double> c2(C2.x, C2.y);
  complex<double> A = conj(c2 - c1),
                  B = (r2 * r2 - r1 * r1 - (c2 - c1) * conj(c2 - c1)),
                  C = r1 * r1 * (c2 - c1);
  complex<double> D = B * B - 4.0 * A * C;
  complex<double> z1 = (-B + sqrt(D)) / (2.0 * A) + c1,
                  z2 = (-B - sqrt(D)) / (2.0 * A) + c1;
  return pair<Point, Point>(Point(z1.real(), z1.imag()),
                            Point(z2.real(), z2.imag()));
}

// ------

bool LT(double a, double b) { return !equals(a, b) && a < b; }
bool LTE(double a, double b) { return equals(a, b) || a < b; }

bool isValid(Point p) {
  return LTE(-100.0, p.x) && LTE(p.x, 100.0) && LTE(-100.0, p.y) &&
         LTE(p.y, 100.0);
}

vector<Point> base(3), ps(3);

Point vir;
bool cmp_dist(const Point &p1, const Point &p2) {
  return LT(abs(vir - p1), abs(vir - p2));
}

// seg.p1 ??? base ?????????????????§???????????¨
// * 6
bool checkIntersect(Point p, Segment seg1, Segment seg2) {

  // baseSeg ??¨ seg1 ????????? seg2
  // ??????????????¨?????°???????????????????§???¢???????????????
  rep(i, 3) {
    Segment baseSeg = Segment(base[i], base[(i + 1) % 3]);
    if (equals(cross(baseSeg.p1 - baseSeg.p2, seg1.p1 - seg1.p2), 0) &&
        equals(cross(baseSeg.p1 - baseSeg.p2, seg2.p1 - seg2.p2), 0))
      return false;
  }

  // ?????§???????????´???????????§?????????????????§???????????§????????????????????????????§???¢??¨??????????????????????????§????????????
  Segment segs[2] = {seg1, seg2};
  rep(i, 2) {
    Segment seg = segs[i];
    rep(j, 3) {
      Segment baseSeg = Segment(base[j], base[(j + 1) % 3]);
      if (intersectSS(seg, baseSeg)) {
        if (equals(cross(seg.p1 - seg.p2, baseSeg.p1 - baseSeg.p2), 0)) {
          // if( equals(cross(seg.p1-seg.p2,baseSeg.p1-baseSeg.p2),0) && seg.p1
          // == baseSeg.p1 ) { int res = ccw(seg.p1,seg.p2,baseSeg.p2); if( res
          // == ONLINE_FRONT || res == ON_SEGMENT ) return false;

          vector<Point> vec;
          vec.push_back(seg.p1);
          vec.push_back(seg.p2);
          vec.push_back(baseSeg.p1);
          vec.push_back(baseSeg.p2);
          sort(vec.begin(), vec.end());
          // vir = vec[0];
          // sort(vec.begin(),vec.end(),cmp_dist);
          vec.erase(unique(vec.begin(), vec.end()), vec.end());
          rep(i, (int)vec.size() - 1) {
            Point mp = (vec[i] + vec[i + 1]) / 2.0;
            if (onSegment(seg.p1, seg.p2, mp) &&
                onSegment(baseSeg.p1, baseSeg.p2, mp))
              return false;
          }

          continue;
        }
        Point cp = crosspoint(seg, baseSeg);
        if (!(cp == seg.p1))
          return false;
      }
    }
  }

  return true;
}

inline bool check(Point p, int j) {
  // ??????????????????????????????p????????¨?????????
  if (!isValid(p))
    return false;

  // ????????????????§???¢??¨?????????????????????????§?????????°????????????

  // ????????????????§???¢???????????\\?§????????????????????????????
  // if( inPolygon(base,p,true) ) return false;
  // return !inPolygon(base,p,true);
  double cs[3];

  rep(i, 3) {
    if (onSegment(base[i], base[(i + 1) % 3], p))
      return false;
    Point a = base[(i + 1) % 3] - base[i];
    Point b = p - base[i];
    cs[i] = cross(a, b);
  }
  if (LT(cs[0], 0) && LT(cs[1], 0) && LT(cs[2], 0))
    return false;
  if (LT(0, cs[0]) && LT(0, cs[1]) && LT(0, cs[2]))
    return false;

  if (!checkIntersect(p, Segment(base[j], p), Segment(base[(j + 1) % 3], p)))
    return false;

  return true;
  // return checkIntersect(p,Segment(base[i],p),Segment(base[(i+1)%3],p));
}

//???????????????????????????????????????????????????????????????????????§??????
bool FinalCheck(int limit = 3) {
  Line lines[3][2];
  rep(i, limit) lines[i][0] = Line(base[i], ps[i]),
                lines[i][1] = Line(base[(i + 1) % 3], ps[i]);
  rep(i, limit) {
    REP(j, i + 1, limit) {
      if (ps[i] == ps[j])
        return false;
      rep(k, 2) {
        Segment ururu_beam1 = lines[i][k];
        rep(l, 2) {
          Segment ururu_beam2 = lines[j][l];
          if (intersectSS(ururu_beam1, ururu_beam2)) {
            Point cp = crosspoint(ururu_beam1, ururu_beam2);
            if (cp == ururu_beam1.p1 && cp == ururu_beam2.p1)
              continue;
            return false;
          }
        }
      }
    }
  }
  return true;
}

double getH() {

  Line lines[3];
  rep(i, 3) {
    Vector e = (base[i] - base[(i + 1) % 3]) / abs(base[i] - base[(i + 1) % 3]);
    e = rotate(e, toRad(90.0));
    lines[i] = Line(ps[i], ps[i] + e * 1000);
  }

  Point cp = crosspoint(lines[0], lines[1]);
  rep(i, 3) if (cp == ps[i]) return 1e30;

  Point onBaseP0 = crosspoint(lines[0], Line(base[0], base[1]));

  double a = abs(cp - onBaseP0);
  double b = abs(onBaseP0 - ps[0]);
  if (equals(a, b))
    return 1e30;
  if (LTE(b, a))
    return 1e30;

  return sqrt(b * b - a * a);
}

void compute() {
  double mini = 1e30;
  REP(x1, -100, 101) {
    if (x1 == 32)
      continue;
    REP(y1, -100, 101) {

      if (!check(Point(x1, y1), 0))
        continue;
      ps[0] = Point(x1, y1);
      double lengthOfPs0ToBase1 = abs(ps[0] - base[1]);
      // REP(x2,-100,101){
      for (int x2 = max(-100, (int)(base[1].x - lengthOfPs0ToBase1));
           x2 <= min(100, (int)(base[1].x + lengthOfPs0ToBase1)); x2++) {
        double diff_x = abs(x2 - base[1].x);
        if (LT(lengthOfPs0ToBase1, diff_x))
          continue;
        double diff_y =
            sqrt(lengthOfPs0ToBase1 * lengthOfPs0ToBase1 - diff_x * diff_x);

        if (!equals(diff_y, (int)(diff_y + EPS)))
          continue;
        for (int coef = -1; coef <= 1; coef += 2) { // ????£????????????????
          double y2 = base[1].y + diff_y * (double)coef;
          if (!(equals(y2, (int)(y2 + EPS)) || equals(y2, (int)(y2 - EPS))))
            continue;
          if (!check(Point(x2, y2), 1))
            continue;
          ps[1] = Point(x2, y2);
          if (!FinalCheck(2))
            continue;
          pair<Point, Point> tmp = crosspointCC(base[0], abs(ps[0] - base[0]),
                                                base[2], abs(ps[1] - base[2]));
          Point tps[2] = {tmp.first, tmp.second};
          bool succ = false;
          rep(i, 2) {
            if (!check(tps[i], 2))
              continue;
            ps[2] = tps[i];

            if (!(equals(ps[2].x, (int)(ps[2].x + EPS)) ||
                  equals(ps[2].x, (int)(ps[2].x - EPS))) ||
                !(equals(ps[2].y, (int)(ps[2].y + EPS)) ||
                  equals(ps[2].y, (int)(ps[2].y - EPS))))
              continue;
            if (!FinalCheck())
              continue;
            double h = getH();
            if (LT(h, mini))
              mini = h;
            if (!equals(h, 1e30)) {
              succ = true;
              break;
            }
          }
          if (succ)
            break;
        }
      }
    }
  }
  if (equals(mini, 1e30))
    puts("-1");
  else
    printf("%.10f\\n", mini);
}

int main() {
  while (1) {
    bool fin = true;
    rep(i, 3) {
      scanf("%lf %lf", &base[i].x, &base[i].y);
      if (!(base[i] == Point(0, 0)))
        fin = false;
    }
    if (fin)
      break;
    compute();
  }
  return 0;
}