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Comment by grakic | Hacker News Reader

Can this program be made any shorter? http://www.dodaj.rs/f/1K/vW/2gLz63rl/blockly.png

Here's one with same amount of code and optimal logic (for this map) without hard coding. It also ensures that there is a forward step in every iteration of the while loop.

Basically it's just an order of preference:

Turn right > turn left > go straight

An "else" would help; you can add one by hitting the + symbol on the if. With the else, you can get the shortest program that'll solve the maze (transcribing using approximate notation in lieu of a screenshot):

    while True:
        if wall(AHEAD):
            turn(LEFT)
        else:
            move(FORWARD)
            turn(RIGHT)

However, the addition of one more if makes the solution much faster and look more sensible, by not turning to the right and immediately back to the left:

    while True:
        if wall(AHEAD):
            turn(LEFT)
        else:
            move(FORWARD)
            if not wall(RIGHT):
                turn(RIGHT)

You can add an 'else' clause to the 'if' block by clicking the '+' which launches a sub-editor.

Here's one that runs the fastest through this particular maze (I noticed there's always a wall on the right side when we need to make a left turn):

http://i.imgur.com/gNaRA.png

And a much shorter and dumber version that does the same thing:

http://i.imgur.com/TgS8I.png

http://i.imgur.com/HTvOx.png

Edit: I didn't know that an else was possible, so I had to do it this way.

Weird, that looks like you're manipulating blocks of text with the mouse. How is that a "visual programming language"? It just seems to be a fancy text editor.

It visually represents the grammar of the language with the jigsaw patterns of the keywords, and prohibits connecting bad sequences, etc.

Not the fastest but its just about as short as yours (counting all blocks as one): http://cdn-images.9cloud.us/716/best-solution-kay_1568014138...

I would blur out those browser favorites, if I were you.

indeed

http://i.imgur.com/8D2G9.jpg

Looping left, forward, right, forward works for this particular maze, though it can get caught in potential corners types.

http://i.imgur.com/ct17R.png it takes a while, but gets there.

takes awhile... hard to tell whats "shorter"

  while !wall(AHEAD):
    move forward
    turn left
    while wall(AHEAD):
      turn right

If you started off facing a wall your code would just not do anything. You can both simplify it and fix this bug by reorganizing the loop.

    while true:
        turn left
        while wall(AHEAD):
            turn right
        move forward

However, while this algorithm happens to work on this maze, it will not work against other mazes (if you care).

Imagine a 5x5 square race track, with spokes coming from the outside of the wheel to the center, where there was a flag. Your algorithm (and my modified one) would just spin clockwise around the track without ever realizing it should take a right towards the center.

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