Hi.... Is my code true?

Is my code true?(it is for finding optimization answer,the main problem is in the follow)

function A=string(s)

n=12;

best=0;

i=n/2;

j=n/2;

check=zeros(n,n);

%empty matrix

A=zeros(12,12);

%A(:,:)=[];

s=[2 1 2 1 1 2 1 1 2 1 2 1 2 1 1 ];

len=length(s);

A(i,j)=s(1);

check(i,j)=1;

for l=2:len

y=randperm(4);

switch y(1)

 case 1

j=j-1;

case 2

i=i-1;

case 3

 i=i+1;

case 4

j=j+1;

end

if check(i,j)==0

 A(i,j)=s(l);

check(i,j)=1;

switch y(2)

case 1

j=j-1;

case 2

 i=i-1;

case 3

i=i+1;

case 4

 j=j+1;

end

if check(i,j)==0

 A(i,j)=s(l);

check(i,j)=1;

end switch y(3)

case 1

j=j-1;

case 2

 i=i-1;

case 3

i=i+1;

case 4

 j=j+1;

end

if check(i,j)==0

A(i,j)=s(l);

check(i,j)=1;

end

end

end

%number of zero

num1=nnz(s);

num2=len-num1;

% andis of zero

w=find(A==0);

for z=1:num2

if w(i+1)==w(i)==2

 best=best+1;

end

end

best

A

end

the string includes 0 and 1:

with 2 conditions:the nodes can be in four directions in a matrix & the edges connect 2 nodes dont cut each other & nodes(0&1) dont put on each other. The value of optimization calculate with couple node 0 and the distance between 2 couple nodes is 1. for example for string s1 =

and its graph is= red nodes show 1 , black nodes show 0 and blue lines show couple nodes.

in my code I replace 2 instead of zero.I dont understand how to find edge for writing optimization??

Thanks for all answers...

[Geoff Hayes]

Helena - it may be worthwhile to add some comments to your code so that we can see how the lines of code relate to the above problem. Once you have done that, consider attaching the revised version (the m file) to your question using the paperclip button (rather than pasting in the 100+ lines like you have done above).