Competitive_Programming/src/Geometry/LineGeometry.java at master · pct960/Competitive_Programming · GitHub

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packageGeometry;
importjava.util.*;

publicclassLineGeometry {

staticfinaldoubleEPS = 1e-10;

publicstaticintsign(doublea) {
returna < -EPS ? -1 : a > EPS ? 1 : 0;
	}

publicstaticclassPointimplementsComparable<Point> {
publicdoublex, y;

publicPoint(doublex, doubley) {
this.x = x;
this.y = y;
 }

publicPointminus(Pointb) {
returnnewPoint(x - b.x, y - b.y);
 }

publicdoublecross(Pointb) {
returnx * b.y - y * b.x;
 }

publicdoubledot(Pointb) {
returnx * b.x + y * b.y;
 }

publicPointrotateCCW(doubleangle) {
returnnewPoint(x * Math.cos(angle) - y * Math.sin(angle), x * Math.sin(angle) + y * Math.cos(angle));
 }

@Override
publicintcompareTo(Pointo) {
// return Double.compare(Math.atan2(y, x), Math.atan2(o.y, o.x));
returnDouble.compare(x, o.x) != 0 ? Double.compare(x, o.x) : Double.compare(y, o.y);
 }
	}

publicstaticclassLine {
publicdoublea, b, c;

publicLine(doublea, doubleb, doublec) {
this.a = a;
this.b = b;
this.c = c;
 }

publicLine(Pointp1, Pointp2) {
a = +(p1.y - p2.y);
b = -(p1.x - p2.x);
c = p1.x * p2.y - p2.x * p1.y;
 }

publicPointintersect(Lineline) {
doubled = a * line.b - line.a * b;
if (sign(d) == 0) {
returnnull;
 }
doublex = -(c * line.b - line.c * b) / d;
doubley = -(a * line.c - line.a * c) / d;
returnnewPoint(x, y);
 }
	}

// Returns -1 for clockwise, 0 for straight line, 1 for counterclockwise order
publicstaticintorientation(Pointa, Pointb, Pointc) {
PointAB = b.minus(a);
PointAC = c.minus(a);
returnsign(AB.cross(AC));
	}

publicstaticbooleancw(Pointa, Pointb, Pointc) {
returnorientation(a, b, c) < 0;
	}

publicstaticbooleanccw(Pointa, Pointb, Pointc) {
returnorientation(a, b, c) > 0;
	}

publicstaticbooleanisCrossIntersect(Pointa, Pointb, Pointc, Pointd) {
returnorientation(a, b, c) * orientation(a, b, d) < 0 && orientation(c, d, a) * orientation(c, d, b) < 0;
	}

publicstaticbooleanisCrossOrTouchIntersect(Pointa, Pointb, Pointc, Pointd) {
if (Math.max(a.x, b.x) < Math.min(c.x, d.x) - EPS || Math.max(c.x, d.x) < Math.min(a.x, b.x) - EPS
 || Math.max(a.y, b.y) < Math.min(c.y, d.y) - EPS || Math.max(c.y, d.y) < Math.min(a.y, b.y) - EPS) {
returnfalse;
 }
returnorientation(a, b, c) * orientation(a, b, d) <= 0 && orientation(c, d, a) * orientation(c, d, b) <= 0;
	}

publicstaticdoublepointToLineDistance(Pointp, Lineline) {
returnMath.abs(line.a * p.x + line.b * p.y + line.c) / fastHypot(line.a, line.b);
	}

publicstaticdoublefastHypot(doublex, doubley) {
returnMath.sqrt(x * x + y * y);
	}

publicstaticdoublesqr(doublex) {
returnx * x;
	}

publicstaticdoubleangleBetween(Pointa, Pointb) {
returnMath.atan2(a.cross(b), a.dot(b));
	}

publicstaticdoubleangle(Lineline) {
returnMath.atan2(-line.a, line.b);
	}

publicstaticdoublesignedArea(Point[] points) {
intn = points.length;
doublearea = 0;
for (inti = 0, j = n - 1; i < n; j = i++) {
area += (points[i].x - points[j].x) * (points[i].y + points[j].y);
// area += points[i].x * points[j].y - points[j].x * points[i].y;
 }
returnarea / 2;
	}

publicstaticenumPosition {
LEFT, RIGHT, BEHIND, BEYOND, ORIGIN, DESTINATION, BETWEEN
	}

// Classifies position of point p against vector a
publicstaticPositionclassify(Pointp, Pointa) {
ints = sign(a.cross(p));
if (s > 0) {
returnPosition.LEFT;
 }
if (s < 0) {
returnPosition.RIGHT;
 }
if (sign(p.x) == 0 && sign(p.y) == 0) {
returnPosition.ORIGIN;
 }
if (sign(p.x - a.x) == 0 && sign(p.y - a.y) == 0) {
returnPosition.DESTINATION;
 }
if (a.x * p.x < 0 || a.y * p.y < 0) {
returnPosition.BEYOND;
 }
if (a.x * a.x + a.y * a.y < p.x * p.x + p.y * p.y) {
returnPosition.BEHIND;
 }
returnPosition.BETWEEN;
	}

// cuts right part of poly (returns left part)
publicstaticPoint[] convexCut(Point[] poly, Pointp1, Pointp2) {
intn = poly.length;
List<Point> res = newArrayList<>();
for (inti = 0, j = n - 1; i < n; j = i++) {
intd1 = orientation(p1, p2, poly[j]);
intd2 = orientation(p1, p2, poly[i]);
if (d1 >= 0)
res.add(poly[j]);
if (d1 * d2 < 0)
res.add(newLine(p1, p2).intersect(newLine(poly[j], poly[i])));
 }
returnres.toArray(newPoint[res.size()]);
	}

// Usage example
publicstaticvoidmain(String[] args) {
	}
}