Just a random question regarding switch case efficiency in case after case; is the following code (assume pseudo code):

function bool isValid(String myString){
   switch(myString){
   case "stringA":
   case "stringB":
   case "stringC":
      return true;
   default:
      return false;
}

more efficient than this:

function bool isValid(String myString){
   switch(myString){
   case "stringA":
      return true;
   case "stringB":
      return true;
   case "stringC":
      return true;
   default:
      return false;
}

Or is the performance equal? I'm not thinking in a specific language but if needed let's assume it's Java or C (for this case would be needed to use chars instead of strings).