MATLAB: How to avoid the rows not to get repeated again

Question

If the run the following code it works.

M=rand(14); 
for N=2:5
    c=randperm(length(M),N)  
    B=M(c,:) % output matrix
end

but the rows are getting repeated again and again .How can i avoid the duplicate rows not to get repeat it again .

Answer 1

M=rand(14);a=1:14;
for N=2:5
    c=randsample(a,N)
    B=M(c,:);
    [~,idx]=find(ismember(a,c));
    if N==5
    else
    a(idx)=[];
    end
end