gistfile1.txt

		uint8_t row_counts[4];
		for(int row = 0; row < NUM_ROWS; row++)
			for(int col = 0; col < NUM_COLUMNS; col++)
				row_counts[row] += (scan[col] >> row) & 1;
		
		for(int col = 0; col < NUM_COLUMNS; col++) {
			uint8_t column_count = set_bits[scan[col]];
			
			for(int row = 0; row < NUM_ROWS; row++) {
				if(row_counts[row] > 1 && column_count > 1)
					// Key may be ghosted; skip it
					continue;
				
				
			}
		}