How to get origin vector form indexd matrix

I have a 1xK row vector A generated by randi function, and K is even number

K=6;
A = randi([50 500],1,K);

A will rearrage by a K/2x1 index matrix which the index matrix is obtained from some algorithm, for example

idx = [1 3;4 5;2 6];
B = A(idx);

I want to get a vector C same as A from B, but I can't do

C = A

in my case. How should I do?

Very appreciate for any suggestion.

Answer 1

[Jan]

K   = 6;
A   = randi([50 500], 1, K)

A = 1×6

71 409 445 202 193 95

idx = [1 3;4 5;2 6];
B   = A(idx)

B = 3×2

71 445 202 193 409 95

C(idx) = B

C = 1×6

71 409 445 202 193 95

Of course, because if you omit the indirection over B you have:

C(idx) = A(idx)

which is an exact copy.

[WJ]

Thanks for the answer, that is what I want.

Answer 2

[Scott MacKenzie]

idx2 = [1 3 4 2 5 6];
C = B(idx2)

[WJ]

Thanks for answer, but the idx will be dynamic not fix.

[Scott MacKenzie]

Ok, got it. See Jan's answer. He's nailed it.