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								id: 5900f3d21000cf542c50fee5
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								challengeType: 5
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								title: 'Problem 102: Triangle containment'
							 
						 
					
						
							
								
									
										
										
										
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								forumTopicId: 301726
							 
						 
					
						
							
								
									
										
										
										
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								## Description
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< section  id = 'description' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								Three distinct points are plotted at random on a Cartesian plane, for which -1000 ≤ x, y ≤ 1000, such that a triangle is formed.
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								Consider the following two triangles:
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								A(-340,495), B(-153,-910), C(835,-947)
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								X(-175,41), Y(-421,-714), Z(574,-645)
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								It can be verified that triangle ABC contains the origin, whereas triangle XYZ does not.
							 
						 
					
						
							
								
									
										
										
										
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								Using triangles.txt (right click and 'Save Link/Target As...'), a 27K text file containing the coordinates of one thousand "random" triangles, find the number of triangles for which the interior contains the origin.
							 
						 
					
						
							
								
									
										
										
										
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								NOTE: The first two examples in the file represent the triangles in the example given above.
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
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								## Instructions
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< section  id = 'instructions' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
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								## Tests
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< section  id = 'tests' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								```yml
							 
						 
					
						
							
								
									
										
										
										
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								tests:
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								  -  text: < code > euler102()</ code >  should return 228.
							 
						 
					
						
							
								
									
										
										
										
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								    testString: assert.strictEqual(euler102(), 228);
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
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								## Challenge Seed
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< section  id = 'challengeSeed' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< div  id = 'js-seed' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								function euler102() {
							 
						 
					
						
							
								
									
										
										
										
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								  return true;
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								euler102();
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
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								## Solution
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								< section  id = 'solution' > 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								// solution required
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
							
								```
							 
						 
					
						
							
								
									
										
										
										
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