Matrix sequence manipulation for multiple value assignment

Is there a quick (& simple) way to do the following without a loop? Not even sure why I don't want loops but still figured it'd be nice to know if there was a way. Feels like something obvious I'm just not thinking of..

I have an array and a matrix of indices, e.g.

A = zeros(20, 1);
idxes = [1,  5; ...
         10, 13; ...
         19, 20];

and I'd like to convert it such that the following is achieved without hardcoding in the indices:

A([1:5, 10:13, 19:20]) = 1;

Equivalent solution with a loop:

for i = 1:size(idxes, 1)
    A(idxes(i, 1):idxes(i, 2)) = 1
end

Answer 1

[Matt J]

If the intervals will always be disjoint,

A=zeros(20,1); 
n=numel(A);
A(idxes(:,1))=1; A(idxes(:,2)+1)=-1;

A=cumsum(A(1:n))

Answer 2

[Matt J]

e=1:numel(A);
lidx= any(idxes(:,1)<=e & e<=idxes(:,2),1);
A(lidx)=1;