How to make this javascript code using a matrix work with App Inventor to count matrix inversions?

[SteveJG]

How to make this javascript code using a matrix work with App Inventor to count matrix inversions.

javascript matrix inversion source and example:

Solvable and unsolvable matrix situations incorrectly report as Solvable in App Inventor. A matrix inversion of [[8, 1, 2],[5, 4, 3],[7, 6, 0]] correctly reports unsolvable (odd number of inversions counted) (when run in JSFiddle but not in AI where 0 inversions are counted.

What am I missing? Advice would be appreciated.

Here us what I have:

matrixSNjavascript.aia (3.2 KB)

Thanks for any advice.
-- Steve

[TIMAI2]

Try like this in html/js (not tested):
Note the conversion of the webviewstring to an array object - puzzleObj.

// This function returns true 
// if given 8 puzzle is solvable. 
function isSolvable(puzzleObj) { 
	// Count inversions in given 8 puzzle 
	let invCount = getInvCount(puzzleObj);
	// return true if inversion count is even. 
	return (invCount % 2 == 0);
}

// Driver code

// Value 0 is used for empty space

puzzle = window.AppInventor.getWebViewString();
puzzleObj = JSON.parse(puzzle);
document.write("matrix: " + puzzle)

document.write("inversions: " +getInvCount(puzzle));

//unsolvable
//puzzle = [[8, 1, 2],[5, 4, 3],[7, 6, 0]] ;

//puzzle = [[8, 1, 2],[0, 4, 3],[7, 6, 5]] ;
// puzzle = [[1, 8, 2],[0, 4, 3],[7, 6, 5]] ;

if(isSolvable(puzzleObj)) {
	document.write("Solvable");
        //document.write(inv_count);
}
else {
	document.write("Not Solvable");
}	

[SteveJG]

Thanks for quick response Tim. Your code needs a little help to produce a correct solution Not Solvable.

puzzle = window.AppInventor.getWebViewString();
puzzleObj = JSON.parse(puzzle);
puzzle = puzzleObj;
document.write("matrix: " + puzzle)

---

Now on AI I get :
3 inversions : 8,1,2,5,3,7,6 Not Solvable which is the same solution shown with JSFiddle.

Your hint helped solve the code, now I need to make it look pretty and get Not Solvable into Label2.

[TIMAI2]

Odd, that shouldn't work (I expected [object][Object]) but hey ho, away we go

[SteveJG]

Thanks to @TIMAI2 , the javascript solution is part of

"

Slide Nine - *a sliding block puzzle game tutorial for App Inventor*

A JavaScript inversions algorithm now attempts to determine if a 3 x 3 sliding puzzle is solvable . The tool is now part of Slide Nine (SlideNine_solvable.aia ). I am not sure how robust the article algorithm is; it appears to be reliable. A forecast of solvability is automatically provided at the start of the puzzle. Also check if a move within a solvable puzzle leaves the puzzle still solvable or not. Use the 'S' button to find out if a move you just made still allows the puzzle to be…