Should do hip re surfacing or total hip replacement for young patient of 26 years of age. Does after surgery there is change in legs length.?

Usually not. Unless there was shorting before, I do not think so.
Both good options. The decision to have either hip resurfacing or total hip replacement is one that you need to discuss with your orthopaedic surgeon. There are advantages and disadvantages for both procedures. The younger the patient at the time of surgery, the more careful the decision should be made- further surgery in 15-20 years may be necessary and needs to be realized before the first surgery.