Related vector values via cell array

Hi guys, I hope someone can help me:

I have a vector. Suppose this:

A=(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)'

Some values of this vector are related through a cell array, in such a way that a value of the vector is the index of a cell. I need to know if a value of the vector "a" is related to another value "b".

B={15, 12, 0, [11, 7], 9, 0, [1, 20, 21], 18, 7, 0, 16, [13, 14], 17, 4, 6};
a=2; b=7

In this case, 2 and 7 are related:

Index       Value
2             12
12            13,14
13            17
17            Nan
14            4
4             7

So, a=5 and b=6; and a=4 and b=1 are also related.

Thanks to the whole community

[Matt J]

The way you determine that a is related to b is not clear, at least not to me.

[Sergio Rojas Blanco]

Sorry, it's a little weird

Index 2->12. Now, I take this value (12) like the new index

Index 12->13 and 14. Now, I take one of theses (13, the first) and I follow the sequence

Index 13->17, I follow the sequence

Index 17->Nan. If there isn't any value in the cell or it's zero, the sequence (with 13) would end here. But now, I take the other value (14, the sencond) and I follow the sequence

Index 14->4. I follow the sequence

Index 4->7. I have arrived to "b" starting from "a"

I hope you understand a little better now.

Thanks

[Dyuman Joshi]

By this logic, a=4 and b=1 are related.

B={15, 12, 0, [11, 7], 9, 0, [1, 20, 21], 18, 7, 0, 16, [13, 14], 17, 4, 6};

Idx 4 - 11

Idx 11 - 16

Idx 16 - NaN

Idx 4 - 7

Idx 7 - 1

Related.

[Sergio Rojas Blanco]

You're rigth. I have edited to remove the error

[Dyuman Joshi]

@Sergio Rojas Blanco, please check my answer.

Answer 1

[Dyuman Joshi]

A=(1:10)';
B={15, 12, 0, [11, 7], 9, 0, [1, 20, 21], 18, 7, 0, 16, [13, 14], 17, 4, 6};
m = max([B{:}]);

z1 = nested(A,B,2,7)

z1 = 1

%8th index is 18 which is greater than the number of elements
%so no value is related to it
z2 = nested(A,B,8,randi(m))

z2 = 0

%3rd index is 0, so no value related to it
z3 = nested(A,B,3,randi(m))

z3 = 0

%Similarly for 6th index
z4 = nested(A,B,6,randi(m))

z4 = 0

z5 = nested(A,B,5,6)

z5 = 1

%As the 1st index in B goes to the 6th index, no value will be related to it as well
z6 = nested(A,B,1,randi(m))

z6 = 0

function z = nested(A,B,a,b)
%Returns 0 if not related, 1 if related

%Initialize z as 0
z=0;
nB=numel(B);

for m=1:numel(a)
    %Assign only if the value is within the range of number of elements of B
    if a(m)<=nB && a(m)>0
        c=B{a(m)};
    else
    %If the value is not in the range, skip to the next iteration
        continue
    end
    %Check if b is present in c or not
    if ismember(b,c)
        z=1;
        return
    else
    %If not present, continue the recursion and keep checking
        z=nested(A,B,c,b);
        end
    end
end

[Sergio Rojas Blanco]

Thanks a lot Dyuman. I have gained a lot of time with your code.

[Dyuman Joshi]

Glad to have helped!