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  1. #include <iostream>
  2. 	#include <algorithm>
  3. 	#include <vector>
  4. 	#include <array>
  5.  
  6. 	struct Point
  7. 	{
  8. 		size_t x;
  9. 		size_t y;
  10. 		Point() : x(0), y(0) {}
  11. 		Point(size_t x, size_t y) : x(x), y(y) {}
  12.  
  13. 		Point operator+(const Point& p) const
  14. 		{
  15. 			return Point(x + p.x, y + p.y);
  16. 		}
  17.  
  18. 		bool operator==(const Point& p) const
  19. 		{
  20. 			return x == p.x && y == p.y;
  21. 		}
  22. 	};
  23.  
  24. 	const std::array<Point, 4> clockwise {
  25. 		Point(+1, 0), //right
  26. 		Point(0, +1), //down
  27. 		Point(-1, 0), //left
  28. 		Point(0, -1), //up
  29. 	};
  30.  
  31. 	const std::array<Point, 4> counterClockwise {
  32. 		Point(0, +1), //down
  33. 		Point(+1, 0), //right
  34. 		Point(0, -1), //up
  35. 		Point(-1, 0), //left
  36. 	};
  37.  
  38. 	struct Grid
  39. 	{
  40. 		std::vector<std::vector<int>> grid;
  41. 		size_t size;
  42.  
  43. 		Grid(size_t size)
  44. 		{
  45. 			this->size = size;
  46. 			for(size_t i = 0; i < size; i++)
  47. 			{
  48. 				grid.push_back(std::vector<int>(size));
  49. 				std::fill(grid[i].begin(), grid[i].end(), 0);
  50. 			}
  51. 		}
  52.  
  53. 		bool withinBounds(const Point& p)
  54. 		{
  55. 			return 0 <= p.x && p.x < size && 0 <= p.y && p.y < size;
  56. 		}
  57.  
  58. 		void fill(bool reverse)
  59. 		{
  60. 			Point current(0, 0);
  61. 			size_t directionIndex = 0;
  62. 			auto direction = reverse ? counterClockwise : clockwise;
  63. 			for(int number = 1, end = size * size; number <= end; number++)
  64. 			{
  65. 				grid[current.y][current.x] = number;
  66. 				auto next = current + direction[directionIndex];
  67. 				if(!withinBounds(next) || grid[next.y][next.x] != 0)
  68. 				{
  69. 					directionIndex = (directionIndex + 1) % 4;
  70. 					next = current + direction[directionIndex];
  71. 				}
  72. 				current = next;
  73. 			}
  74. 		}
  75.  
  76. 		friend std::ostream& operator<<(std::ostream& out, const Grid& g);
  77. 	};
  78.  
  79. 	std::ostream& operator<<(std::ostream& out, const Grid& g)
  80. 	{
  81. 		for(size_t y = 0; y < g.size; y++)
  82. 		{
  83. 			for(size_t x = 0; x < g.size; x++)
  84. 			{
  85. 				out << g.grid[y][x] << '\t';
  86. 			}
  87. 			out << std::endl;
  88. 		}
  89. 		return out;
  90. 	}
  91.  
  92. 	int main()
  93. 	{
  94. 		int n;
  95. 		std::string direction;
  96. 		std::cin >> n;
  97. 		std::cin >> direction;
  98.  
  99. 		Grid grid(n);
  100. 		grid.fill(direction == "reverse");
  101. 		std::cout << grid << std::endl;
  102. 	}
Success #stdin #stdout 0s 16064KB
comments ()
stdin 
4
reverse
stdout 
1	12	11	10	
2	13	16	9	
3	14	15	8	
4	5	6	7
https://ideone.com/5Y1Al3
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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