jfbouzereau / unblock

Solve UNBLOCK-ME puzzles

UNBLOCK

This javascript program solves unblock me types of puzzle :

It does not try to optimize the search, and uses brute force algorithm with backtracking.

IN NODE.JS

The game must be described in a json file. Example 601.json :

{
	"nrow":6,
	"ncol":6,
	"exit":"r",
	"pieces":[
		{"dir":"h","len":2,"row":2,"col":0},
		{"dir":"h","len":2,"row":0,"col":0},	
		{"dir":"v","len":2,"row":0,"col":3},
		{"dir":"h","len":2,"row":0,"col":4},
		{"dir":"h","len":3,"row":1,"col":0},
		{"dir":"v","len":3,"row":1,"col":5},
		{"dir":"v","len":2,"row":3,"col":0},
		{"dir":"h","len":2,"row":3,"col":1},
		{"dir":"h","len":2,"row":3,"col":3},
		{"dir":"v","len":2,"row":4,"col":2},
		{"dir":"h","len":3,"row":4,"col":3},		
		{"dir":"h","len":2,"row":5,"col":0}
	]
}

• nrow is the number of rows of the field

• ncol is the number of colums of the field

• exit is exit side : top (t) bottom (b) left (l) right (r)

• pieces is the array of pieces

  The first piece MUST BE the target (usually the red piece)

  dir specifies if the piece is horizontal (h) or vertical (v)

  len is the length of the piece (1,2 or 3)

  row and col specify the left-most or top-most position of the piece

  fix is set to true if the piece cannot move

EXECUTION

Run

node unblock.js 601.json

If everything is OK, the solution is displayed one step after each other. Example :

  1  1  .  2  3  3
  4  4  4  2  .  5
  0  0  .  .  .  5
  6  7  7  8  8  5
  6  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
1 : piece 0 to right
  1  1  .  2  3  3
  4  4  4  2  .  5
  .  0  0  .  .  5
  6  7  7  8  8  5
  6  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
2 : piece 2 to bottom
  1  1  .  .  3  3
  4  4  4  2  .  5
  .  0  0  2  .  5
  6  7  7  8  8  5
  6  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
3 : piece 3 to left
  1  1  .  3  3  .
  4  4  4  2  .  5
  .  0  0  2  .  5
  6  7  7  8  8  5
  6  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
4 : piece 5 to top
  1  1  .  3  3  5
  4  4  4  2  .  5
  .  0  0  2  .  5
  6  7  7  8  8  .
  6  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
5 : piece 6 to top
  1  1  .  3  3  5
  4  4  4  2  .  5
  6  0  0  2  .  5
  6  7  7  8  8  .
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
6 : piece 8 to right
  1  1  .  3  3  5
  4  4  4  2  .  5
  6  0  0  2  .  5
  6  7  7  .  8  8
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
7 : piece 2 to bottom
  1  1  .  3  3  5
  4  4  4  .  .  5
  6  0  0  2  .  5
  6  7  7  2  8  8
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
8 : piece 4 to right
  1  1  .  3  3  5
  .  4  4  4  .  5
  6  0  0  2  .  5
  6  7  7  2  8  8
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
9 : piece 6 to top
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  .  7  7  2  8  8
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
10 : piece 7 to left
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  7  7  .  2  8  8
  .  .  9 10 10 10
 11 11  9  .  .  .
-------------------------
11 : piece 9 to top
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  7  7  9  2  8  8
  .  .  9 10 10 10
 11 11  .  .  .  .
-------------------------
12 : piece 11 to right
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  7  7  9  2  8  8
  .  .  9 10 10 10
  .  .  . 11 11  .
-------------------------
13 : piece 9 to bottom
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  7  7  .  2  8  8
  .  .  9 10 10 10
  .  .  9 11 11  .
-------------------------
14 : piece 7 to right
  1  1  .  3  3  5
  6  4  4  4  .  5
  6  0  0  2  .  5
  .  7  7  2  8  8
  .  .  9 10 10 10
  .  .  9 11 11  .
-------------------------
15 : piece 6 to bottom
  1  1  .  3  3  5
  .  4  4  4  .  5
  6  0  0  2  .  5
  6  7  7  2  8  8
  .  .  9 10 10 10
  .  .  9 11 11  .
-------------------------
16 : piece 4 to left
  1  1  .  3  3  5
  4  4  4  .  .  5
  6  0  0  2  .  5
  6  7  7  2  8  8
  .  .  9 10 10 10
  .  .  9 11 11  .
-------------------------
17 : piece 2 to top
  1  1  .  3  3  5
  4  4  4  2  .  5
  6  0  0  2  .  5
  6  7  7  .  8  8
  .  .  9 10 10 10
  .  .  9 11 11  .
-------------------------
18 : piece 6 to bottom
  1  1  .  3  3  5
  4  4  4  2  .  5
  .  0  0  2  .  5
  .  7  7  .  8  8
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
19 : piece 7 to left
  1  1  .  3  3  5
  4  4  4  2  .  5
  .  0  0  2  .  5
  7  7  .  .  8  8
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
20 : piece 8 to left
  1  1  .  3  3  5
  4  4  4  2  .  5
  .  0  0  2  .  5
  7  7  .  8  8  .
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
21 : piece 5 to bottom
  1  1  .  3  3  .
  4  4  4  2  .  5
  .  0  0  2  .  5
  7  7  .  8  8  5
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
22 : piece 3 to right
  1  1  .  .  3  3
  4  4  4  2  .  5
  .  0  0  2  .  5
  7  7  .  8  8  5
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
23 : piece 2 to top
  1  1  .  2  3  3
  4  4  4  2  .  5
  .  0  0  .  .  5
  7  7  .  8  8  5
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
24 : piece 0 to right
  1  1  .  2  3  3
  4  4  4  2  .  5
  .  .  .  0  0  5
  7  7  .  8  8  5
  6  .  9 10 10 10
  6  .  9 11 11  .
-------------------------
25 : piece 9 to top
  1  1  .  2  3  3
  4  4  4  2  .  5
  .  .  9  0  0  5
  7  7  9  8  8  5
  6  .  . 10 10 10
  6  .  . 11 11  .
-------------------------
26 : piece 10 to left
  1  1  .  2  3  3
  4  4  4  2  .  5
  .  .  9  0  0  5
  7  7  9  8  8  5
  6  . 10 10 10  .
  6  .  . 11 11  .
-------------------------
27 : piece 5 to bottom
  1  1  .  2  3  3
  4  4  4  2  .  .
  .  .  9  0  0  .
  7  7  9  8  8  5
  6  . 10 10 10  5
  6  .  . 11 11  5
-------------------------
28 : piece 0 to right
  1  1  .  2  3  3
  4  4  4  2  .  .
  .  .  9  .  0  0
  7  7  9  8  8  5
  6  . 10 10 10  5
  6  .  . 11 11  5
-------------------------

IN THE BROWSER

In the browser several features are available :

• You can build the puzzle interactively. Choose the size of the field, then use the mouse to position the various pieces.

• You can export the puzzle just built in the previous step.

• You can import a json file by dropping it to the initial form.

• You can solve the puzzle with the solve button.

• Once the solution is computed, you can play it with the play button.

TECHNICAL NOTES

• unblock.js is used both as a node.js application and as a webworker. It must be noted that the javascript engines of the various browsers have different performances. Here are some average resolution times in seconds, on an idle macbook air :

Target	1.json	1f.json	601.json
node.js 10.13	1	90	10
Chrome 77.0	1	70	8
Safari 13.0	3	200	20
Firefox 70.0	2	150	15

• The stack size in the browser is usually smaller than in node.js. A puzzle requiring 2500 levels of recursion would crash in the browser with a stack overflow error. To avoid this, a trick using generator and async function is used. That way, each level of recursion occurs asynchronously in the bottom level of the stack. The drawback is that the execution time is somehow longer.

• Safari allows to load a webworker from a local file. Others browsers will not. You must for example serve the files from a http server started with :

python -m SimpleHTTPServer 8000