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  1.  
  2. class SearchInMatrix {
  3.  
  4. 	/**
  5. 	 * @param args
  6. 	 */
  7. 	public static void main(String[] args) {
  8. 		int[][]  mat = new int[][] { {10, 20, 30, 40},{15, 25, 35, 45}, {27, 29, 37, 48},{32, 33, 39, 50}};
  9. 		int rowcount = 4,colCount=4,key=50;
  10. 		for(int i=0;i<rowcount; i++)
  11. 			for(int j=0;j<colCount; j++)
  12. 				search(mat,0,rowcount-1,0,colCount-1,mat[i][j]);
  13. 	}
  14.  
  15. 	public static void search(int[][] mat,int fromRow,int toRow,int fromCol, int toCol,int key){
  16. 		// Search middle key. 
  17. 		// If middle key is lesser then search lower horizontal matrix and right hand side matrix
  18. 		// If middle key is greater then search left vertical matrix and right hand side matrix
  19. 		int i = fromRow+ (toRow-fromRow )/2;
  20. 		int j = fromCol+ (toCol-fromCol )/2;
  21. 		if(mat[i][j]==key){
  22. 			System.out.println("Found "+key+ " at "+ i + " " + j);
  23. 		}else {
  24. 			// right hand side matrix
  25. 			// Provided it is different than current call
  26. 			if(i!=toRow || j!=fromCol){
  27. 				search(mat,fromRow,i,j,toCol,key);
  28. 			}
  29. 			// Special case for iteration with 1*2 matrix
  30. 			// mat[i][j] and mat[i][j+1] are only two elements.
  31. 			// So just check second element
  32. 			if(fromRow == toRow && fromCol +1 == toCol){
  33. 				if(mat[fromRow][toCol] ==  key){
  34. 					System.out.println("Found "+key+ " at "+ fromRow + " " + toCol);
  35. 				}
  36. 			}
  37.  
  38. 			if(mat[i][j]<key){
  39. 				// search lower horizontal matrix. 
  40. 				// Provided such matrix exists
  41. 				if(i+1<=toRow){
  42. 					search(mat,i+1,toRow,fromCol,toCol,key);
  43. 				}else{
  44. 					//System.out.println("Such lower matrix doe not exisit");
  45. 				}
  46. 			}else{
  47. 				// left vertical matrix 
  48. 				// Provided such matrix exists
  49. 				if(j-1>=fromCol){
  50. 					search(mat,fromRow,toRow,fromCol,j-1,key);
  51. 				}else{
  52. 					//System.out.println("Such vertical matrix doe not exisit");
  53. 				}
  54. 			}
  55.  
  56. 			}
  57. 		}
  58. }
Success #stdin #stdout 0.07s 380224KB
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stdin
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Standard input is empty
stdout
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Found 10 at 0 0
Found 20 at 0 1
Found 30 at 0 2
Found 40 at 0 3
Found 15 at 1 0
Found 25 at 1 1
Found 35 at 1 2
Found 45 at 1 3
Found 27 at 2 0
Found 29 at 2 1
Found 37 at 2 2
Found 48 at 2 3
Found 32 at 3 0
Found 33 at 3 1
Found 39 at 3 2
Found 50 at 3 3
https://ideone.com/zJ29vW
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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