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  1. #include <vector>
  2. #include <memory>	// for auto_ptr
  3. #include <cmath>	// for the log10 and floor functions
  4. #include <iostream>
  5. #include <iomanip>	// for the setw function
  6.  
  7. using namespace std;
  8.  
  9. typedef vector< int > IntRow;
  10. typedef vector< IntRow > IntTable;
  11.  
  12. auto_ptr< IntTable > getZigZagArray( int dimension )
  13. {
  14. 	auto_ptr< IntTable > zigZagArrayPtr( new IntTable(
  15. 		dimension, IntRow( dimension ) ) );
  16.  
  17. 	// fill along diagonal stripes (oriented as "/")
  18. 	int lastValue = dimension * dimension - 1;
  19. 	int currNum = 0;
  20. 	int currDiag = 0;
  21. 	int loopFrom;
  22. 	int loopTo;
  23. 	int i;
  24. 	int row;
  25. 	int col;
  26. 	do
  27. 	{
  28. 		if ( currDiag < dimension ) // if doing the upper-left triangular half
  29. 		{
  30. 			loopFrom = 0;
  31. 			loopTo = currDiag;
  32. 		}
  33. 		else // doing the bottom-right triangular half
  34. 		{
  35. 			loopFrom = currDiag - dimension + 1;
  36. 			loopTo = dimension - 1;
  37. 		}
  38.  
  39. 		for ( i = loopFrom; i <= loopTo; i++ )
  40. 		{
  41. 			if ( currDiag % 2 == 0 ) // want to fill upwards
  42. 			{
  43. 				row = loopTo - i + loopFrom;
  44. 				col = i;
  45. 			}
  46. 			else // want to fill downwards
  47. 			{
  48. 				row = i;
  49. 				col = loopTo - i + loopFrom;
  50. 			}
  51.  
  52. 			( *zigZagArrayPtr )[ row ][ col ] = currNum++;
  53. 		}
  54.  
  55. 		currDiag++;
  56. 	}
  57. 	while ( currDiag <= lastValue );
  58.  
  59. 	return zigZagArrayPtr;
  60. }
  61.  
  62. void printZigZagArray( const auto_ptr< IntTable >& zigZagArrayPtr )
  63. {
  64. 	size_t dimension = zigZagArrayPtr->size();
  65.  
  66. 	int fieldWidth = static_cast< int >( floor( log10(
  67. 		static_cast< double >( dimension * dimension - 1 ) ) ) ) + 2;
  68.  
  69. 	size_t col;
  70. 	for ( size_t row = 0; row < dimension; row++ )
  71. 	{
  72. 		for ( col = 0; col < dimension; col++ )
  73. 			cout << setw( fieldWidth ) << ( *zigZagArrayPtr )[ row ][ col ];
  74. 		cout << endl;
  75. 	}
  76. }
  77.  
  78. int main()
  79. {
  80. 	printZigZagArray( getZigZagArray( 5 ) );
  81. }
Success #stdin #stdout 0.01s 5520KB
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  0  1  5  6 14
  2  4  7 13 15
  3  8 12 16 21
  9 11 17 20 22
 10 18 19 23 24
https://ideone.com/1mPMui
language:
C++ (gcc 8.3)
created:
2 years ago
visibility:
public

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