如何在游戏Hangman中使用3D阵列？

 public static String[] getWords(int cat, int diff)
{
String topic[][][] = new String[3][3][3];
switch(cat){
  case 0:
  topic[0][0][0] = "Paris";
  topic[0][0][1] = "London";
  topic[0][0][2] = "Sydney";
 diff = 0;
  topic[0][1][0] = "Toronto";
  topic[0][1][1] = "Florida";
  topic[0][1][2] = "Frankfurt";
diff = 1;
  topic[0][2][0] = "Barcelona";
  topic[0][2][1] = "Vancouver";
  topic[0][2][2] = "Zimbabwe";
 diff = 2;
case 1:
  topic[1][0][0] = "Halo";  
  topic[1][0][1] = "Fifa";                   
  topic[1][0][2] = "GTA";
  diff = 0;                  
  topic[1][1][0] = "Skyrim";
  topic[1][1][1] = "HITMAN";
  topic[1][1][2] = "Batman";
diff =1;
  topic[1][2][0] = "Minecraft";
  topic[1][2][1] = "Zombieville";
  topic[1][2][2] = "BoderLands";
  diff =2;
  case 2:
  topic[2][0][0] = "Acura";
  topic[2][0][1] = "Audi";
  topic[2][0][2] = "Bmw";
 diff = 0;
  topic[2][1][0] = "Bentley";
  topic[2][1][1] = "Buggati";
  topic[2][1][2] = "Honda";
  diff = 1;
  topic[2][2][0] = "Lamborghini";
  topic[2][2][1] = "Rolls-Royce";
  topic[2][2][2] = "Mercedes";
  diff = 2;
  }
  return topic[cat][diff];
 public static String[] getWords(int cat, int d