function [A u] = place_N_queens_cols_rows(N)
% this function places N queens on the NxN board, 
% no two queens are in the same row or column.
% Only diagonal attacks are possible.

A = zeros(N);
p = randperm(N);
q = randperm(N);
    for i = 1 : N
        A(p(i), q(i)) = 1;
    end
end