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  1. #include<stdio.h>
  2. #include<limits.h>
  3. #include<math.h>
  4. struct point
  5. {
  6. 	float x1;
  7. 	float y1;
  8. };
  9.  
  10. float findratio(float x,float y, struct point *a)
  11. {
  12. 	if(x!=a[0].x1)
  13. 	{
  14. 	return (a[1].x1-x)/(x-a[0].x1);	
  15. 	}
  16. 	else 
  17. 	{
  18. 	return (a[1].y1-y)/(y-a[0].y1);
  19. 	}	
  20. }
  21. float findratioSlopesame(struct point * a, struct point* b)
  22. {
  23. 	float m;
  24. 	m=findratio(a[0].x1,a[0].y1,b);
  25. 	if(m>0)
  26. 	return m;
  27. 	m=findratio(a[1].x1,a[1].y1,b);
  28. 	if(m>0)
  29. 	return m;
  30. 	m=findratio(b[0].x1,b[0].y1,a);
  31. 	if(m>0)
  32. 	return m;
  33. 	m=findratio(b[0].x1,b[0].y1,a);
  34. 	if(m>0)
  35. 	return m;
  36. 	return -1;
  37.  
  38. }
  39. float findslope(struct point *a)
  40. {
  41. 	if(a[0].x1==a[1].x1)
  42. 	{
  43. 		return INFINITY;
  44. 	}
  45. 	else
  46. 	{
  47. 		return (a[1].y1-a[0].y1)/(a[1].x1-a[0].x1);
  48. 	}
  49. }
  50. int check (struct point *a, struct point *b)
  51. {
  52. 	if((a[0].y1<=b[0].y1&& a[0].y1>=b[1].y1)||(a[1].y1<=b[0].y1&& a[1].y1>=b[1].y1) )
  53. 	return 1;
  54. 	else if((a[0].y1<=b[1].y1&& a[0].y1>=b[0].y1)||(a[1].y1<=b[1].y1&& a[1].y1>=b[0].y1) )
  55. 	return 1;
  56. 	return 0;
  57. }
  58. int intersection(struct point *a, struct point *b,struct point *p)
  59. {
  60. float m1=findslope(a);
  61. float m2=findslope(b);
  62.  
  63. if(m1==INFINITY && m2==INFINITY)
  64. {
  65.  
  66. 	if(a[0].x1==b[1].x1)
  67. 	{
  68. 		//check whether 1st line contains another line 
  69.  
  70. 		if(check(a,b)||check(b,a))
  71. 		{
  72. 			return 1;
  73. 		}
  74. 	}
  75. 	else
  76. 	{
  77. 		p->x1=INFINITY;
  78. 		p->y1=INFINITY;
  79. 		return 0;
  80. 	}
  81.  
  82. }
  83.  
  84. else if (m1!=INFINITY && m2!=INFINITY && m1!=m2)
  85. {
  86.  
  87. 	float x=(b[0].y1-a[0].y1-(m2*b[0].x1)+(m1*a[0].x1))/(m1-m2);
  88. 	float y=a[0].y1+m1*(x-a[0].x1);
  89. 	p->x1=x;
  90. 	p->y1=y;
  91. 	if(findratio(x,y,a)>=0 && findratio(x,y,b)>=0)
  92. 	return 1;
  93. 	else 
  94. 	return 0;
  95.  
  96. } 
  97. else if (m1==m2)
  98. {
  99. 	//y=mx+c1 y=mx+c2 checking c1-c2
  100. 	float x=a[0].y1-m1*a[0].x1;
  101. 	float y=b[0].y1-m1*b[0].x1;
  102. 	if(x!=y)
  103. 	return 0;
  104. 	if((a[0].x1==b[0].x1 && a[0].y1==b[0].y1)||(a[1].x1==b[0].x1 && a[1].y1==b[0].y1)||(a[0].x1==b[1].x1 && a[0].y1==b[1].y1)||(a[1].x1==b[1].x1 && a[1].y1==b[1].y1))
  105. 	return 1;
  106.  	if(findratioSlopesame(a,b)>0||findratioSlopesame(b,a)>0)
  107. 	return 1;
  108. 	return 0;
  109. }
  110. else if(m1!=m2)
  111. {
  112. 	if(m1==INFINITY)
  113. 	{
  114.  
  115. 		float x=a[0].x1;
  116. 		float y=b[0].y1+m2*(x-b[0].x1);
  117. 		if((x==a[0].x1&& y==a[0].y1)||(x==a[1].x1&& y==a[1].y1)||(x==b[0].x1&& y==b[0].y1)||(x==b[1].x1&& y==b[1].y1))
  118. 		{
  119. 			return 1;
  120. 		}
  121. 		if(findratio(x,y,a)>0|| findratio(x,y,b)>0)
  122. 		return 1;
  123. 		else 
  124. 		return 0;
  125. 	}
  126. 	else if (m2==INFINITY)
  127. 	{
  128. 		float x=b[0].x1;
  129. 		float y=a[0].y1+m1*(x-a[0].x1);
  130. 		if((x==a[0].x1&& y==a[0].y1)||(x==a[1].x1&& y==a[1].y1)||(x==b[0].x1&& y==b[0].y1)||(x==b[1].x1&& y==b[1].y1))
  131. 		{
  132. 			return 1;
  133. 		}
  134. 		if(findratio(x,y,a)>0|| findratio(x,y,b)>0)
  135. 		return 1;
  136. 		else 
  137. 		return 0;
  138. 	}
  139.  
  140. }
  141.  
  142. }
  143.  
  144.  
  145. int main()
  146. {
  147. 	struct point l1[2];
  148. 	struct point l2[2];
  149. 	scanf("%f %f %f %f",&l1[0].x1,&l1[0].y1,&l1[1].x1,&l1[1].y1);
  150.  
  151. 	scanf("%f %f %f %f",&l2[0].x1,&l2[0].y1,&l2[1].x1,&l2[1].y1);
  152. 	//findintersection
  153. 	// tells the 
  154. 	struct point p;
  155. 	int result=intersection(l1,l2,&p);
  156. 	if(result==0)
  157. 	{
  158. 		printf("\nNo");
  159. 	}
  160. 	else
  161. 	{
  162. 			printf("\nYes");
  163. 	}
  164. 	return 0;
  165. }
Success #stdin #stdout 0s 9432KB
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https://ideone.com/6jEsgV
language:
C (gcc 8.3)
created:
5 years ago
visibility:
public

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