根据规则复杂度O（n3）优化将文件移动到另一个文件夹

Question

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 contains 25000 values with value from file nameOfFiles
    copyfile(char(imNames(i)), nameOfFiles); % copies file to a folder nameOfFiles      
            end
           end
         end  

Answer 1

As nekomantic said parfor actually slowed my program. Also my algorithm could be reduced to O(n2). I didn't actually need the outside for . I also moved my algorithm in c++ and it moves 1000x faster . Thank you for your help .

for k=1:38
nameOfFiles=filenames(k).name;
     nameOfFiles=erase(nameOfFiles,'.txt');
    for o=1:length(data.(nameOfFiles))

            copyfile(data(o).(nameOfFiles), nameOfFiles);
            disp(o)
         end
end