# Problem of mathematics and programming

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Suppose I have an array stored 50 data, data are just '0' and '1' The probability of occurrence of '0' is 0.1 The probability of occurrence of '1' is 0.9

So there are five '0' and forty-five '1' and suppose the five '0' are appeared first.

The sequence is :{0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,.....,1}

I want to find out all the sequenes which the '0' are located at different position.

ie: the five '0' are placed at every different locations

Can matlab function solve this question? how to implement to solve this?

### Answers (5)

Walter Roberson
on 31 Jan 2013

##### 0 Comments

Jonathan Epperl
on 31 Jan 2013

Like Walter said, what you are ultimately looking for are all the combinations you obtain from drawing 5 out of 50 without replacement, so nchoosek(50,5). Matlab will give you a matrix where each row is one combination

M = nchoosek(1:50,5);

You'll get your 0s and 1s then by (and I'm sure there are better ways):

M = nchoosek(1:50,5);

Z = ones(10,size(M,1));

MM = M + (0:size(M,1)-1)'*10*ones(1,size(M,2));

Z(MM)=0;

imagesc(Z')

##### 0 Comments

Youssef Khmou
on 31 Jan 2013

Edited: Youssef Khmou
on 31 Jan 2013

suppose your vector is

V=[0 0 0 0 0 1 1 1 1 1];

to find the positions you try :

[value,index]=find(V==0)

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