Putting 1's in certain places - matlab

Question

I have 2 matrices
Matrix A = [7 3 5 2 8 4 1 6 9;
5 2 6 1 4 3 9 7 8;
9 1 4 5 2 6 3 6 7;
4 8 1 6 3 7 2 9 5;
6 1 7 2 8 4 5 9 3]
Matrix B = [1 0 0 0 0 0 0 0 0;
0 1 1 0 0 0 0 0 0;
0 0 0 0 0 0 0 1 0;
0 0 0 1 0 1 0 0 0;
0 0 0 0 0 0 0 0 1]
Matrix A and B are already defined.
Here each column can't have more than 1 what i want to do is that if when i do sum for Matrix B if i found 0 in it i have to add 1's in the places of the zero's but in certain places. In each row the 1's have to be placed in certain groups. For example if a 1 is placed in column 1, then it can be placed as well in column 2 or 3 only. It can't be placed anywhere else. If in another row it is placed in column 5, then it can be placed in column 4 or 6 only and so on. It's like group of 3. Each 3 columns are together.
To be more clear:
Here the sum of matrix B is [1 1 1 1 0 1 0 1 1]. The zeros here are placed in column 5 and 7 and i want to add 1 putting in mind where the 1 is going to be placed in the matrix. So in this example the 1 of column 5 can only be placed in row 4 as the 1's in this row are placed in column 4 and 6. The 1 of column 7 can be placed in row 5 or row 3. If we have choice between 2 rows then the 1 will be placed in the placed of the higher number of Matrix A.
The 1's have to be placed in groups; columns 1, 2 and 3 are together, columns 4,5 and 6 are together and columns 7, 8 and 9 are together. so if the 1 is placed in 1 column of the group then it can't be placed in any other place.
Let me simplify it if we have an array like this [0 0 0 0 0 0 0 1 1] This array has 3 categories, columns 1,2 and 3 are 1st category, columns 4,5 and 6 are 2nd category and so on. here i want to place a 1 so that the 3rd category won't have a zero element. This is what i want to do briefly but with a whole matrix with all the categories.
so here the output will be =
[1 0 0 0 0 0 0 0 0;
0 1 1 0 0 0 0 0 0;
0 0 0 0 0 0 0 1 0;
0 0 0 1 1 1 0 0 0;
0 0 0 0 0 0 1 0 1]
This code was tried but it doesn't give the required output as the 1 was placed in the 1st row not in the place where it has to be (the category that it should be in).
sum_cols_B = sum(B); % Sum of Matrix B (dim 1)
[~, idx] = find(sum_cols_B == 0); % Get indices where sum == 0
% Using loop to go through the indices (where sum = 0)
for ii = idx
B(1,ii) = 1; % Insert 1 in the first position of that
end % column in Matrix B
Ask me if the question is still not clear.!

Answer 1

Here's an updated loop that will add the missing 1's:
sum_cols_B = sum(B);
[~, idx] = find(sum_cols_B == 0);
group_size = 3;
for ii = idx
% Calculate the starting column of the group for column ii
% There are (ii-1)/group_size groups
% Add 1 for 1-based indexing
group_start = floor((ii-1)/group_size)*group_size + 1;
% Determine which rows in the current group have nonzero values
group_mask = sum(B(:,group_start:group_start+group_size-1), 2) > 0;
% Find the row number of the max in A column ii corresponding to mask
[~,rownum] = max(A(:,ii).*group_mask);
% The value in column ii of B should have a 1 inserted
% at the row containing the max in A
B(rownum,ii) = 1;
end
Results for B above are:
B =
1 0 0 0 0 0 0 0 0
0 1 1 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0
0 0 0 1 1 1 0 0 0
0 0 0 0 0 0 1 0 1

Answer 2

B = [1 0 0 0 0 0 0 0 0;...
0 1 1 0 0 0 0 0 0;...
0 0 0 0 0 0 0 1 0;...
0 0 0 1 0 1 0 0 0;...
0 0 0 0 0 0 0 0 1]; % Matrix - using this as an example
sum_cols_B = sum(B); % Sum of Matrix B (dim 1)
[~, idx] = find(sum_cols_B == 0); % Get indices where sum == 0
% Using loop to go through the indices (where sum = 0)
for ii = idx
B(1,ii) = 1; % Insert 1 in the first position of that
end % column in Matrix B