tortoiseSVN:Revision range to merge option ,why show this result?

[loveSVN]

http://stackoverflow.com/questions/19075623/tortoisesvnrevision-range-to-merge-option-why-show-this-result
   
  
 mrge range:4-5,8
  
 why 7777 8888 not conflicted?? 
  why 22222 3333 4444 is conflicted?? 
  
 What is merging algorithm SVN use?