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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6. import java.awt.geom.Point2D;
  7.  
  8. /* Name of the class has to be "Main" only if the class is public. */
  9. class Ideone
  10. {
  11. 	static class CPoint extends Point2D.Double
  12. 	{
  13. 		int id;
  14. 		double theta;
  15. 		CPoint prev, next;
  16.  
  17. 		public CPoint(int id, double x, double y)
  18. 		{
  19. 			super(x, y);
  20. 			this.id = id;
  21. 			theta = Math.atan2(y, x);
  22. 			if(theta < 0) theta = 2*Math.PI + theta;
  23. 		}
  24.  
  25. 		public String toString()
  26. 		{
  27. 			return String.format("%d : (%f,%f) : %f [(%f,%f) : (%f,%f)]", id, getX(), getY(), theta, prev.getX(), prev.getY(), next.getX(), next.getY());
  28. 		}
  29. 	}
  30.  
  31. 	public static void main(String[] args)
  32. 	{
  33. 		double[][] coords = {{-0.708, 0.707, 0.309, -0.951, 0.587, -0.809},
  34. 				               {1, 0, 0, 1, -1, 0, 0, -1, 0.708, -0.708}};
  35.  
  36. 		double areaSum = 0;
  37.  
  38. 		List<CPoint> pts = new ArrayList<>();
  39. 		for(int i=0; i<coords.length; i++)
  40. 		{
  41. 			List<CPoint> poly = new ArrayList<>();
  42. 			for(int j=0; j<coords[i].length; j+=2)
  43. 			{
  44. 				poly.add(new CPoint(i, coords[i][j], coords[i][j+1]));
  45. 			}
  46.  
  47. 			poly.sort((a, b) -> Double.compare(a.theta, b.theta));
  48. 			pts.addAll(poly);
  49.  
  50. 			int n = poly.size();
  51. 			for(int j=0; j<n; j++)
  52. 			{
  53. 				poly.get(j).prev = poly.get((j + n - 1) % n);
  54. 				poly.get(j).next = poly.get((j + 1) % n);				
  55. 			}
  56.  
  57. 			areaSum += area(poly);
  58. 		}		
  59.  
  60. 		pts.sort((a, b) -> Double.compare(a.theta, b.theta));
  61.  
  62. 		List<Point2D> intersections = new ArrayList<>();
  63. 		int n = pts.size();
  64. 		for(int i=0, j=n-1; i<n; j=i++)
  65. 		{
  66. 			if(pts.get(j).id != pts.get(i).id)
  67. 			{
  68. 				intersections.add(intersect(pts.get(j), pts.get(j).next, pts.get(i).prev, pts.get(i)));
  69. 			}
  70. 		}
  71.  
  72. 		double areaInt = area(intersections);
  73. 		double iou = areaInt/(areaSum - areaInt);
  74. 		System.out.println(iou);
  75. 	}
  76.  
  77. 	static double area(List<? extends Point2D> poly)
  78. 	{
  79. 		double area = 0;
  80. 		for(int i=0, j=poly.size()-1; i<poly.size(); j=i++)
  81. 			area += (poly.get(j).getX() * poly.get(i).getY()) - (poly.get(i).getX() * poly.get(j).getY());
  82. 		return Math.abs(area)/2;
  83. 	}
  84.  
  85. 	// https://r...content-available-to-author-only...e.org/wiki/Find_the_intersection_of_two_lines#Java
  86. 	static Point2D intersect(Point2D p1, Point2D p2, Point2D p3, Point2D p4)
  87. 	{
  88. 	  double a1 = p2.getY() - p1.getY();
  89. 	  double b1 = p1.getX() - p2.getX();
  90. 	  double c1 = a1 * p1.getX() + b1 * p1.getY();
  91.  
  92. 	  double a2 = p4.getY() - p3.getY();
  93. 	  double b2 = p3.getX() - p4.getX();
  94. 	  double c2 = a2 * p3.getX() + b2 * p3.getY();
  95.  
  96. 	  double delta = a1 * b2 - a2 * b1;
  97. 	  return new Point2D.Double((b2 * c1 - b1 * c2) / delta, (a1 * c2 - a2 * c1) / delta);    
  98. 	}
  99. }
Success #stdin #stdout 0.09s 48172KB
comments (?)
stdin 
Standard input is empty
stdout 
0.12403616470027268
https://ideone.com/q6crQL
language:
Java (HotSpot 12)
created:
2 years ago
visibility:
public

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