Graph with stripes in different colors based on 1D array that contain strings which indicate colors

Dear Matlab users

I have 1x3600 array that contain strings such as “B”, “G”, “Y” or “R” that correspond to certain color. In example “B” = BLUE, “G” = GREEN, “Y”=YELLOW, “R”=RED. In fact one string represent 1 second. In example 3 strings “B” means 3 blue seconds, 5 strings “R” means 5 red seconds, etc. On this picture you can see how the array looks like.

I need to create graph that will looks like the graph on this picture. As you can see at x axis should be values from 1 to 3600 with 1 second interval.

Please let me know...how to do this in Matlab? Thank you in advance.