CODEWITHSUNDEEP
matlabsequence
user3.14259
user3.14259

Reputation: 111

Using Matlab to write a sequence

I'm struggling to write this question into Matlab Code. I know that I should use a 'for' loop, but I don't know how to use this to do it. Consider the following sequence of row vectors v(n) for n ≥ 1:

v(1) = (1)

v(2) = (1, 1)

v(3) = (2, 1)

v(4) = (1, 2, 1, 1)

v(5) = (1, 1, 1, 2, 2, 1)

v(6) = (3, 1, 2, 2, 1, 1)

Each row is given by reading out the contents of the row above, so for example v(6) contains “three ones, two twos, one one” and this gives v6. Write a script to print v(n) for n = 1 up to n = 12.

Upvotes: 0

Views: 132

Answers (1)

Yvon
Yvon

Reputation: 2983

One possible version:

N = 6;
v = cell(N,1);
v{1} = 1;
for ii = 2:N
    v1 = v{ii-1};
    stop_point = find(diff(v1));
    if isempty(stop_point)
        n = length(v1);
        m = v1(1);
        v{ii} = [n,m];
    else
        n = diff([0,stop_point,length(v1)]);
        m = v1([stop_point,end]);
        v2 = [n;m];
        v{ii} = v2(:).';
    end
end

Example output: 

>> v{:}

ans =

     1


ans =

     1     1


ans =

     2     1


ans =

     1     2     1     1


ans =

     1     1     1     2     2     1


ans =

     3     1     2     2     1     1

>>

Note: Row vectors of unequal lengths cannot be contained in a matrix. An easy way to store them is using a cell array.

Upvotes: 1

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