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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4. import java.text.*;
  5. import java.util.function.*;
  6. import static java.lang.Math.*;
  7.  
  8. class Util {
  9. 	static IllegalArgumentException badArgf(String fmt, Object... args) {
  10. 		return new IllegalArgumentException(String.format(fmt, args));
  11. 	}
  12.  
  13. 	static final DecimalFormat humanFloatFormat = new DecimalFormat("#.###");
  14.  
  15. 	static String humanFloat(double x) {
  16. 		return humanFloatFormat.format(x);
  17. 	}
  18.  
  19. 	static String trace(Exception e) {
  20. 		StringWriter sw = new StringWriter();
  21. 		e.printStackTrace(new PrintWriter(sw));
  22. 		return sw.toString();
  23. 	}
  24. }
  25.  
  26. class Vec2 {
  27. 	public final double x, y;
  28. 	public Vec2(double x, double y) { this.x = x; this.y = y; }
  29. 	public static Vec2 Vec2(double x, double y) { return new Vec2(x, y); }
  30. 	public Vec2 add(Vec2 b) { return Vec2(x + b.x, y + b.y); }
  31. 	public Vec2 sub(Vec2 b) { return Vec2(x - b.x, y - b.y); }
  32. 	public Vec2 mul(Vec2 b) { return Vec2(x * b.x, y * b.y); }
  33. 	public Vec2 mul(double b) { return Vec2(x * b, y * b); }
  34. 	public Vec2 div(Vec2 b) { return Vec2(x / b.x, y / b.y); }
  35. 	public Vec2 div(double b) { return Vec2(x / b, y / b); }
  36. 	@Override public String toString() { return String.format("(%s, %s)", Util.humanFloat(x), Util.humanFloat(y)); }
  37. 	public Vec2 min(Vec2 b) { return Vec2(Math.min(x, b.x), Math.min(y, b.y)); }
  38. 	public Vec2 max(Vec2 b) { return Vec2(Math.max(x, b.x), Math.max(y, b.y)); }
  39. }
  40.  
  41. class AABB {
  42. 	public final Vec2 a, b;
  43. 	public AABB(Vec2 a, Vec2 b) { this.a = a; this.b = b; }
  44. 	public static AABB AABB(Vec2 a, Vec2 b) { return new AABB(a, b); }
  45. 	@Override public String toString() { return String.format("A = %s, B = %s", a, b); }
  46.  
  47. 	public static AABB bound(int count, IntFunction<AABB> ithBB) {
  48. 		if (count <= 0) throw Util.badArgf("AABB.bound: count = %d.", count);
  49. 		var bb = ithBB.apply(0);
  50. 		Vec2 a = bb.a, b = bb.b;
  51. 		for (int i = 1; i < count; i++) {
  52. 			bb = ithBB.apply(i);
  53. 			a = a.min(bb.a);
  54. 			b = b.max(bb.b);
  55. 		}
  56. 		return AABB(a, b);
  57. 	}
  58.  
  59. 	public static AABB bound(List<AABB> bbs) {
  60. 		if (bbs.size() == 0) throw Util.badArgf("AABB.bound: count = %d.", bbs.size());
  61. 		var bb = bbs.get(0);
  62. 		Vec2 a = bb.a, b = bb.b;
  63. 		for (int i = 1; i < bbs.size(); i++) {
  64. 			bb = bbs.get(i);
  65. 			a = a.min(bb.a);
  66. 			b = b.max(bb.b);
  67. 		}
  68. 		return AABB(a, b);
  69. 	}
  70.  
  71. 	public static AABB bound(Iterator<AABB> bbs) {
  72. 		if (!bbs.hasNext()) throw Util.badArgf("AABB.bound: no items.");
  73. 		var bb = bbs.next();
  74. 		Vec2 a = bb.a, b = bb.b;
  75. 		while (bbs.hasNext()) {
  76. 			bb = bbs.next();
  77. 			a = a.min(bb.a);
  78. 			b = b.max(bb.b);
  79. 		}
  80. 		return AABB(a, b);
  81. 	}
  82. }
  83.  
  84. class MyPreciousObject {
  85. 	AABB bb;
  86. 	Vec2 pos;
  87. 	String name;
  88. 	Object someOtherData;
  89.  
  90. 	public MyPreciousObject(AABB bb) {
  91. 		this.bb = bb;
  92. 	}
  93. }
  94.  
  95. class Ideone
  96. {
  97. 	static double benchmark(String title, Supplier payload) {
  98. 		return benchmark(title, payload, -1);
  99. 	}
  100.  
  101. 	static double benchmark(String title, Supplier payload, double reference) {
  102. 		long start = System.nanoTime();
  103. 		var payloadResult = payload.get();
  104. 		double time = (System.nanoTime() - start) * 1e-9;
  105. 		// использовать payloadResult желательно даже без соответствующего %s, а то мало ли СОПТИМИЗИРУЕТСЯ при неиспользовании.
  106. 		System.out.println(String.format(
  107. 			"%s: %.2f s%s%s",
  108. 			title, time, reference >= 0 ? String.format(" (%s)", judgement(time, reference)) : "",
  109. 			payloadResult != null ? String.format("\n%s\n", payloadResult) : ""));
  110. 		return time;
  111. 	}
  112.  
  113. 	static String judgement(double time, double refTime) {
  114. 		final double absThreshold = 0.1, relThreshold = .1;
  115.  
  116. 		return time <= absThreshold || refTime <= absThreshold ?
  117. 			String.format("can't judge, min. required time is %.1f s", absThreshold) :
  118. 			Math.max(time, refTime) > (1 + relThreshold) * Math.min(time, refTime) ?
  119. 			String.format("%.0f%% %s",
  120. 				Math.abs((time < refTime ? refTime / time : time / refTime) - 1) * 100,
  121. 				time < refTime ? "faster" : "slower") :
  122. 			String.format("no observable difference, min. %.0f%% required", relThreshold * 100);
  123. 	}
  124.  
  125. 	static void benchmark() {
  126. 		var objs = new ArrayList<MyPreciousObject>();
  127. 		var rand = new Random(1);
  128. 		for (int i = 0; i < 1_000_000; i++) {
  129. 			Vec2 a = Vec2.Vec2(rand.nextDouble(), rand.nextDouble()).mul(100);
  130. 			objs.add(new MyPreciousObject(
  131. 				AABB.AABB(a, a.add(Vec2.Vec2(rand.nextDouble(), rand.nextDouble()).mul(10)))
  132. 			));
  133. 		}
  134. 		var bbList = new ArrayList<AABB>();
  135.  
  136. 		final int TRIALS = 3, AMPLIFY = 50;
  137. 		for (int iTrial = 0; iTrial < TRIALS; iTrial++) {
  138. 			System.out.printf("%s--- TRIAL %d/%d ---\n", iTrial > 0 ? "\n" : "", 1 + iTrial, TRIALS);
  139. 			var ref = benchmark("bound(List<AABB>)", () -> {
  140. 				AABB result = null;
  141. 				for (int iAmp = 0; iAmp < AMPLIFY; iAmp++) {
  142. 					bbList.clear();
  143. 					bbList.ensureCapacity(objs.size());
  144. 					for (int i = 0; i < objs.size(); i++)
  145. 						bbList.add(objs.get(i).bb);
  146. 					result = AABB.bound(bbList);
  147. 				}
  148. 				return result;
  149. 			});
  150.  
  151. 			benchmark("bound(int -> AABB)", () -> {
  152. 				AABB result = null;
  153. 				for (int iAmp = 0; iAmp < AMPLIFY; iAmp++)
  154. 					result = AABB.bound(objs.size(), i -> objs.get(i).bb);
  155. 				return result;
  156. 			}, ref);
  157.  
  158. 			benchmark("bound(List<MyPreciousObject>.map(obj -> AABB).iterator)", () -> {
  159. 				AABB result = null;
  160. 				for (int iAmp = 0; iAmp < AMPLIFY; iAmp++)
  161. 					result = AABB.bound(objs.stream().map(obj -> obj.bb).iterator());
  162. 				return result;
  163. 			}, ref);
  164. 		}
  165. 	}
  166.  
  167. 	public static void main (String[] args) throws java.lang.Exception
  168. 	{
  169. 		try {
  170. 			benchmark();
  171. 		} catch (Exception e) {
  172. 			System.out.println(Util.trace(e));
  173. 		}
  174. 	}
  175. }
Success #stdin #stdout 14.4s 250264KB
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stdout
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--- TRIAL 1/3 ---
bound(List<AABB>): 1.46 s
A = (0, 0), B = (109.956, 109.954)

bound(int -> AABB): 1.12 s (31% faster)
A = (0, 0), B = (109.956, 109.954)

bound(List<MyPreciousObject>.map(obj -> AABB).iterator): 2.23 s (53% slower)
A = (0, 0), B = (109.956, 109.954)


--- TRIAL 2/3 ---
bound(List<AABB>): 1.38 s
A = (0, 0), B = (109.956, 109.954)

bound(int -> AABB): 1.03 s (33% faster)
A = (0, 0), B = (109.956, 109.954)

bound(List<MyPreciousObject>.map(obj -> AABB).iterator): 2.14 s (56% slower)
A = (0, 0), B = (109.956, 109.954)


--- TRIAL 3/3 ---
bound(List<AABB>): 1.35 s
A = (0, 0), B = (109.956, 109.954)

bound(int -> AABB): 1.04 s (30% faster)
A = (0, 0), B = (109.956, 109.954)

bound(List<MyPreciousObject>.map(obj -> AABB).iterator): 2.13 s (57% slower)
A = (0, 0), B = (109.956, 109.954)
https://ideone.com/8iKwBz
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

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