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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. // M x N matrix
  5. #define M 10
  6. #define N 10
  7.  
  8. // Below arrays details all 8 possible movements
  9. int row[] = { -1, -1, -1,  0, 0,  1, 1, 1 };
  10. int col[] = { -1,  0,  1, -1, 1, -1, 0, 1 };
  11.  
  12. // check if it is possible to go to pixel (x, y) from 
  13. // current pixel. The function returns false if the pixel
  14. // has different color or it is not a valid pixel
  15. bool isSafe(char mat[M][N], int x, int y, char target)
  16. {
  17.     return x >= 0 && x < N && y >= 0 && y < M 
  18.         && mat[x][y] == target;
  19. }
  20.  
  21. // Flood fill using BFS
  22. void floodfill(char mat[M][N], int x, int y, char replacement)
  23. {	   
  24. 	// create a queue and enqueue starting pixel
  25. 	queue<pair<int, int>> q;
  26. 	q.push({x, y});
  27.  
  28. 	// get target color
  29. 	char target = mat[x][y];
  30.  
  31. 	// run till queue is not empty
  32. 	while (!q.empty()) 
  33. 	{
  34. 		// pop front node from queue and process it
  35. 		pair<int, int> node = q.front();
  36. 		q.pop();
  37.  
  38. 		// (x, y) represents current pixel
  39. 		int x = node.first, y = node.second;
  40.  
  41. 		// replace current pixel color with that of replacement
  42. 		mat[x][y] = replacement;
  43.  
  44. 		// process all 8 adjacent pixels of current pixel and
  45. 		// enqueue each valid pixel
  46. 		for (int k = 0; k < 8; k++)
  47. 		{
  48. 			// if adjacent pixel at position (x + row[k], y + col[k]) is
  49. 			// a valid pixel and have same color as that of current pixel
  50. 			if (isSafe(mat, x + row[k], y + col[k], target))
  51. 			{
  52. 				q.push({x + row[k], y + col[k]});
  53. 			}
  54. 		}
  55. 	}
  56. }
  57.  
  58. // main function
  59. int main()
  60. {
  61. 	// matrix showing portion of the screen having different colors
  62. 	char mat[M][N] =
  63. 	{
  64. 		{ 'Y', 'Y', 'Y', 'G', 'G', 'G', 'G', 'G', 'G', 'G' },
  65. 		{ 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'G', 'X', 'X', 'X' },
  66. 		{ 'G', 'G', 'G', 'G', 'G', 'G', 'G', 'X', 'X', 'X' },
  67. 		{ 'W', 'W', 'W', 'W', 'W', 'G', 'G', 'G', 'G', 'X' },
  68. 		{ 'W', 'R', 'R', 'R', 'R', 'R', 'G', 'X', 'X', 'X' },
  69. 		{ 'W', 'W', 'W', 'R', 'R', 'G', 'G', 'X', 'X', 'X' },
  70. 		{ 'W', 'B', 'W', 'R', 'R', 'R', 'R', 'R', 'R', 'X' },
  71. 		{ 'W', 'B', 'B', 'B', 'B', 'R', 'R', 'X', 'X', 'X' },
  72. 		{ 'W', 'B', 'B', 'X', 'B', 'B', 'B', 'B', 'X', 'X' },
  73. 		{ 'W', 'B', 'B', 'X', 'X', 'X', 'X', 'X', 'X', 'X' }
  74. 	};
  75.  
  76. 	// start node 
  77. 	int x = 3, y = 9;	// target color = &quot;X&quot;
  78.  
  79. 	// replacement color
  80. 	char replacement = 'C';
  81.  
  82. 	// replace target color with replacement color
  83. 	floodfill(mat, x, y, replacement);
  84.  
  85. 	// print the colors after replacement
  86. 	for (int i = 0; i < M; i++) 
  87. 	{
  88. 		for (int j = 0; j < N; j++)
  89. 			cout << setw(2) << mat[i][j];
  90.  
  91. 		cout << endl;
  92. 	}
  93. }
Success #stdin #stdout 0s 16064KB
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stdin
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Standard input is empty
stdout
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 Y Y Y G G G G G G G
 Y Y Y Y Y Y G C C C
 G G G G G G G C C C
 W W W W W G G G G C
 W R R R R R G C C C
 W W W R R G G C C C
 W B W R R R R R R C
 W B B B B R R C C C
 W B B C B B B B C C
 W B B C C C C C C C
https://ideone.com/uRjayD
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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