Moving files to another folder based on a rule Complexity O(n3)

Hello i'm trying to move 25000 of images in 38 folders based on a rule . Each folders represents the class the image belongs to . I also have 38 .txt files that contain the name of images that belong to that class . The complexity of this algoritm is O(n3) , more exactly O(25000*38*~3000). It took me 12 hours to move just 3000 images. It would take me about ~30 days to move all the images. What can I do to optimize my code ?

parfor i=1:length(imNames) %imNames is a vector that contains the name of the 25000 images . 

      for k=1:38 %number of .txt files
           nameOfFiles=filenames(k).name;
 % filenames stores the names of the 38 .txt files 
       nameOfFiles=erase(nameOfFiles,'.txt'); % removing .txt extension of files

       for j =1:length(data.(nameOfFiles)) % length of a particular .txt file(number of images within a file)
          %data is a struct that has 38 fields/classes each field containing the names of images withing a .txt file
      if  strcmp(char(imNames(i)),data(j).(nameOfFiles))  %Compares value of vector that contain 25000 values with value from file nameOfFiles

         copyfile(char(imNames(i)), nameOfFiles); % copies file to a folder nameOfFiles      
        end
       end
     end  
  end