On the advice of Ms. Pac-Man who's worried about him getting overweight, Pac-Man has decided to keep track of his daily Pac-Dot intake. Help him count the number of Pac-Dots on a given path in the maze!
The maze
To help you build your own encoding of the maze, you can get some raw data here.
Pac-Man's journey
In the context of this challenge, the following rules apply:
- First, the good news: the ghosts aren't there.
- Pac-Man always starts his race at the position indicated on the above picture, heading to the East. There is no Pac-Dot at the starting position.
- As long as he's following a straight path, he keeps advancing to the next squares.
- When he encounters a 90° turn without any other available path (orange squares on the map), he automatically and systematically takes the turn.
- When he encounters a junction where several paths are available (green squares on the map), he may either continue on the same direction -- if applicable -- or choose another direction (including doing a U-turn).
- When Pac-Man passes through one of the exits on the middle left or middle right side of the maze, he immediately reappears on the opposite side.
- Pac-Man eats all the Pac-Dots on the path he's following. Once a Pac-Dot has been eaten, it is removed from the maze.
The challenge
Input
You'll be given a string describing Pac-Man's behavior on the junctions that he's going to reach. This string will be made of the following characters:
L: do a 90° turn to the leftR: do a 90° turn to the rightF: go forwards (no direction change)B: go backwards (do a U-turn)
When all characters have been processed, Pac-Man stops at the next junction he encounters.
Output
You have to print or output the number of Pac-Dots eaten along the input path.
Rules
- You can write a full program or a function.
- You can take input in either uppercase or lowercase, as either a string or an array of characters. You may also use other characters (but only one character per direction) or integers in
[0 .. 9]. If you do so, please specify it clearly in your answer. - You can assume that the input is always valid. (The jsFiddle below will detect errors, but you're not supposed to.)
- This is code-golf, so the shortest code in bytes wins.
- Standard loopholes are forbidden.
Hint
It may not be required nor optimal to store the exact shape of the maze.
Test cases and demo
The following test cases -- or any other input -- can be tested in this jsFiddle.
1. Input : ""
Output : 1
Comment: Pac-Man just advances to the first junction, eats the Pac-Dot on it and stops.
2. Input : "L"
Output : 7
3. Input : "FFR"
Output : 13
4. Input : "LFLR"
Output : 17
Comment: Pac-Man will exit on the middle right side and re-appear on the left side.
5. Input : "BBBB"
Output : 2
6. Input : "BRRFFFL"
Output : 15
7. Input : "LFFRLFFFFRF"
Output : 50
8. Input : "BRFRLRFRLFR"
Output : 54
Comment: Pac-Man will exit on the middle left side and re-appear on the right side.
9. Input : "FFLRLFFLLLLFFBFLFLRRRLRRFRFLRLFFFLFLLLLFRRFBRLLLFBLFFLBFRLLR"
Output : 244
Comment: All cleared!
