MATLAB Write a function called queen_check that takes an 8-by-8 logical array ca

Question

MATLAB
Write a function called queen_check that takes an 8-by-8 logical array called board as input. The variable board represents a chessboard where a true element means that there is a queen at the given position (unlike in chess, there can be up to 64 queens!), and false means that there is no piece at the given position. The function returns true if no two queens threaten each other and false otherwise. One queen threatens the other if they are on the same row, on the same column, or on the same diagonal.

Explanation / Answer

function [newboard] = place(board, nqueens)
arrsize=size(board);
nrows=arrsize(1);
ncols=arrsize(2);
newboard=false;
if (nqueens==0) newboard=board;
else

    for i=1:nrows
        for j=1:ncols
            if (testsafe(board, i, j))
                temp=board;
                temp(i,j)=1;
                temp=place(temp,nqueens-1);
             
                if (size(temp)==arrsize)
                    newboard=temp;
                    return;
                end
              
            end
          
        end
    end
  
end

end

function [safe] = testsafe(board, row, col)
safe=true;
if sum(board(row,:)) > 0
    safe=false;
elseif sum(board(:,col))> 0
    safe= false;
elseif sum(diag(board,col-row))>0
    safe= false;
else
    rotated=rot90(board);
    newcol=row;
    newrow=(8-col)+1;

    if sum(diag(rotated,newcol-newrow))>0
        safe= false;
    end
    end
    return;
    end
  
  
    function void = printb(barr, nqueens)
    bsize=size(barr);
    cols=bsize(2);
    rows=bsize(1);
    hitsx=[];
    hitsy=[];
    missx=[];
    missy=[];
  

    for i= 1:rows
        for j=1:cols
            if barr(i,j)
                hitsy(end+1)=rows-i;
                hitsx(end+1)=j;
            else
                missy(end+1)=rows-i;
                missx(end+1)=j;
            end
        end
    end
  
    bx=[-1, cols+1];
    by=[-1, rows+1];
    plot(hitsx,hitsy,'r*',missx,missy,'bo',bx,by,'.');
    tstr=['Plot of ' num2str(nqueens) ' queens placed on ' num2str(rows) ' by ' num2str(cols) ' chessboard'];
    title(tstr);
    end
  

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