CareerCup

The code below should work.

The logic is pretty simple, imagine the keyboard as a matrix. If the keyboard size is 26, it is a matrix with 1 row, 26 columns. When the keyboard size is 13, it is a matrix with 2 row and 13 columns.

All we have to now do is compute the moves from source to destination for each character.

For "Hi"
0,0 -> 0,8 (move by 8 columns -> R8)
0,8 -> 0,9 (move by 1 column -> R1)

def robo_hand_moves(input,keyboard_size)
  char_map = {"A"=>1, "B"=>2, "C"=>3, "D"=>4, "E"=>5, "F"=>6, "G"=>7, "H"=>8, "I"=>9, "J"=>10, "K"=>11, "L"=>12, "M"=>13, "N"=>14, "O"=>15, "P"=>16, "Q"=>17, "R"=>18, "S"=>19, "T"=>20, "U"=>21, "V"=>22, "W"=>23, "X"=>24, "Y"=>25, "Z"=>26}
  len = input.size
  source_x=0
  source_y=0
  robo_moves = []
  for i in (0...input.size)
    char_order = char_map[input[i]]
    dest_x = (char_order/keyboard_size).to_i
    dest_y = (char_order%keyboard_size)
    next_move = robo_moves(source_x,source_y,dest_x,dest_y)
    robo_moves+= next_move unless next_move.empty?
    robo_moves<< "T"
    source_x=dest_x
    source_y=dest_y
  end
  puts robo_moves.join(",")
end

def robo_moves(x1,y1,x2,y2)
  result = []
  row_wise_dist = (x2-x1)
  if(row_wise_dist<0)
    result<<"U"+row_wise_dist.abs.to_s
  elsif(row_wise_dist>0)
    result<<"D"+row_wise_dist.abs.to_s
  end
  col_wise_dist = (y2-y1)
  if(col_wise_dist<0)
    result<<"L"+col_wise_dist.abs.to_s
  elsif(col_wise_dist>0)
    result<<"R"+col_wise_dist.abs.to_s
  end
  result
end


begin
  line = ARGV[0]
  input = line.split(",")
  robo_hand_moves(input[0],input[1].to_i)
end

/**
* Java Solution
* O(n) time complexity and O(1) space complexity
*/
public static void process(String input, int width) {
    int currentRow = 0;
    int currentCol = -1;

    for (int i = 0; i < input.length(); i++) {
      int next = input.charAt(i) - 'A'; //next character

      /** convert next character in to 2D location (row and col) based on input width of keyboard */
      int row = next / width;
      int col = next % width;

      /** move robot hand from currentRow, currentCol to row, col */
      if (row < currentRow) {
        System.out.print("U" + (currentRow - row) + ", ");
      } else if (row > currentRow){
        System.out.print("D" + (row - currentRow) + ", ");
      }

      if (col < currentCol) {
        System.out.print("L" + (currentCol - col) + ", ");
      } else if (col > currentCol){
        System.out.print("R" + (col - currentCol) + ", ");
      }

      if (i < input.length() - 1) {
        System.out.print("T, ");
      } else {
        System.out.print('T');
      }

      /** change currentRow and currentCol to new location */
      currentRow = row;
      currentCol = col;
    }
  }