我被这段代码困住了:Problem:Achildcanhopastaircaseofstepsnin1,2or3stepsatonetime.Givenavalueofn,printallthepermutationsoftheorderinwhichhecanclimbthestaircase.这是我的代码:publicclassHoppingLad{intcount;voidhop(intn,intpresent){if(n==present){count++;System.out.println("\nFinishedtype"+count+"climbing.\n");}els