Find the longest streak of 1's from a vector

Suppose I have a vector of 0's and 1's. How can I find, without for-loop(s), the longest streak of 1's in that vector?

eg. For the vector v=[0,1,0,0,1,1,0,0, 1,1,1,1,1 ,0,1,0,1], I want codes that return: longest streak=5, location=9 .

Any suggestion? Thanks in advance.

Answer 1

[Guillaume]

I'm sure if you search cody you'll find a few of this type of problem. A combination of diff and find should do the trick. For example,

v=[0,1,0,0,1,1,0,0, 1,1,1,1,1 ,0,1,0,1];
vd = diff([0 v 0]); %the 0s ensure that there's always a pair of [+1 -1] in the diff
starts = find(vd == 1);
ends = find(vd == -1); 
[longest_streak, idx] = max(ends-starts);
location = starts(idx);

[Vic]

thanks a lot.

[Image Analyst]

Vic, you can also do it with regionprops() in the Image Processing Toolbox as an alternate method. Not sure it would be any fewer lines of code though.