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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct point {
  5. 	int x;
  6. 	int y;
  7. };
  8.  
  9. int f (point *p, int N, int x, int y) {
  10. 	int i1, i2, n, S, S1, S2, S3, flag;
  11. 	for (n = 0; n < N; n++) {
  12. 		flag = 0;
  13. 		i1 = n < N-1 ? n + 1 : 0;
  14. 		while (flag == 0) {
  15. 			i2 = i1 + 1;
  16. 			if (i2 >= N)
  17. 				i2 = 0;
  18. 			if (i2 == (n < N-1 ? n + 1 : 0))
  19. 				break;
  20. 			S = abs (p[i1].x * (p[i2].y - p[n].y) +
  21. 				p[i2].x * (p[n].y - p[i1].y) +
  22. 				p[n].x  * (p[i1].y - p[i2].y));
  23. 			S1 = abs (p[i1].x * (p[i2].y - y) +
  24. 				p[i2].x * (y - p[i1].y) +
  25. 				x * (p[i1].y - p[i2].y));
  26. 			S2 = abs (p[n ].x * (p[i2].y - y) +
  27. 				p[i2].x * (y - p[n].y) +
  28. 				x * (p[n].y - p[i2].y));
  29. 			S3 = abs (p[i1].x * (p[n].y - y) +
  30. 				p[n].x * (y - p[i1].y) +
  31. 				x * (p[i1].y - p[n].y));
  32. 			if (S == S1 + S2 + S3) {
  33. 				flag = 1;
  34. 				break;
  35. 			}
  36. 			i1 ++;
  37. 			if (i1 >= N)
  38. 				i1 = 0;
  39. 			}
  40. 		if (flag == 0)
  41. 			break;
  42. 	}
  43. 	return flag;
  44. }
  45.  
  46. int main() {
  47. 	int n, x, y;
  48. 	cin >> n >> x >> y;
  49. 	point* p = new point[n];
  50. 	for (int i = 0; i < n; i++)
  51. 		cin >> p[i].x >> p[i].y;
  52. 	cout << (f(p, n, x, y) ? "YES" : "NO");
  53. 	return 0;
  54. }
Success #stdin #stdout 0s 15232KB
comments (?)
stdin
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5 3 1
9 2
3 0
-2 -4
-4 0
-4 5
stdout
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YES
https://ideone.com/ychC7s
Точка
language:
C++ (gcc 8.3)
created:
5 years ago
visibility:
public

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