CareerCup

Here is a sample solution for above input, can be easily converted for dynamic input:

#include <iostream>

using namespace std;

struct block_type
{
	char data;
	bool visited;
};

int main()
{
	char input_array [5][5] = {{'.','.','B','.','.'},
								{'.','.','G','R','R'},
								{'.','.','B','.','.'},
								{'R','.','.','.','.'},
								{'R','.','.','.','.'}};
	block_type array[5][5];
	int i,j,k;
	int  block_count=0;
	for (i =0; i<5; i++)
	{
		for (j= 0; j<5; j++)
		{
			array[i][j].data = input_array[i][j];
			array[i][j].visited = false;
		}
	}
	
	for (i =0; i<5; i++)
	{
		for (j= 0; j<5; j++)
		{
			if(!array[i][j].visited)
			{
				if(array[i][j].data == 'B')
				{
					block_count++;
					// mark all B and G nodes in length as visited
					for (k=i; k<5; k++)
					{
						if(array[k][j].data == 'B' || array[k][j].data == 'G')
						{
							array[k][j].visited = true;
						}
						else
						{
							break;
						}
					}
				}
				
				if(array[i][j].data == 'R')
				{
					block_count++;
					// mark all R and G nodes in width as visited
					for (k=j; k<5; k++)
					{
						if(array[i][k].data == 'R' || array[i][k].data =='G')
						{
							array[i][k].visited = true;
						}
						else
							break;
					}
				}
			}
		}
	}
	
	
	cout << "\n " << block_count << "\n";

	return 0;	
}

What is the logic behind above code?

This solution doesn't work for this case:

char input_array [5][5] = {{'.','.','B','.','.'},
								{'.','.','G','R','R'},
								{'.','.','B','.','.'},
								{'B','.','.','.','.'},
								{'B','.','.','.','G'}};

Because this 2 will miss:
1 horizontal strip from (4,4) to (4,4)
1 vertical strip from (4,4) to (4,4)
so total — 5