ここでの鍵はI wanted to make a display for the player's load out, and wanted to show every possible combination of items that they have
. これにより、在庫にあるアイテムの可能な組み合わせを印刷するだけで済むため、複雑さが大幅に軽減されます。
public class EnumCombinations {
//Commenting out more than 4 items, loooong printout otherwise
public static enum ITEM{
STICK(PlayerSlotPosition.SLOT_ONE),
STONE(PlayerSlotPosition.SLOT_ONE),
EGG(PlayerSlotPosition.SLOT_TWO),
SHOVEL(PlayerSlotPosition.SLOT_TWO);
// PAPER(PlayerSlotPosition.SLOT_THREE),
// DIRT(PlayerSlotPosition.SLOT_THREE);
// DIRT(PlayerSlotPosition.SLOT_THREE);
private ITEM(PlayerSlotPosition pos){
}
}
public static enum PlayerSlotPosition{
SLOT_THREE, SLOT_ONE, SLOT_TWO
}
public static List<List<ITEM>> getItemCombinations(List<ITEM> inventory){
List<ITEM> prefix = new ArrayList<>();
List<List<ITEM>> container = new ArrayList<>();
List<ITEM> remainder;
if(inventory==null){
System.out.println("Printing all item combinations, no inventory");
remainder = new ArrayList<>(Arrays.asList(ITEM.values()));
}
else {
remainder = new ArrayList<>(inventory);
}
getItemCombinations(prefix, remainder, container);
return container;
}
private static void getItemCombinations(List<ITEM> prefix, List<ITEM> remainder, List<List<ITEM>> container){
int n=remainder.size();
if(remainder.isEmpty()){
container.add(prefix);
}
else {
for(int i=0; i<n; i++) {
List<ITEM> r = new ArrayList<>();
List<ITEM> p = new ArrayList<>(prefix);
p.add(remainder.get(i));
for(int j=0; j<remainder.size(); j++){
if(j==i)
continue;
r.add(remainder.get(j));
}
getItemCombinations(p, r, container);
}
}
}
public static void main (String[] args) {
System.out.println(getItemCombinations(null)+"\n");
List<ITEM> playerINV = new ArrayList<>();
playerINV.add(ITEM.STICK);
playerINV.add(ITEM.STONE);
playerINV.add(ITEM.EGG);
System.out.println(getItemCombinations(playerINV));
}
}
出力:
Printing all item combinations, no inventory
[[STICK, STONE, EGG, SHOVEL], [STICK, STONE, SHOVEL, EGG], [STICK, EGG, STONE, SHOVEL], [STICK, EGG, SHOVEL, STONE], [STICK, SHOVEL, STONE, EGG], [STICK, SHOVEL, EGG, STONE], [STONE, STICK, EGG, SHOVEL], [STONE, STICK, SHOVEL, EGG], [STONE, EGG, STICK, SHOVEL], [STONE, EGG, SHOVEL, STICK], [STONE, SHOVEL, STICK, EGG], [STONE, SHOVEL, EGG, STICK], [EGG, STICK, STONE, SHOVEL], [EGG, STICK, SHOVEL, STONE], [EGG, STONE, STICK, SHOVEL], [EGG, STONE, SHOVEL, STICK], [EGG, SHOVEL, STICK, STONE], [EGG, SHOVEL, STONE, STICK], [SHOVEL, STICK, STONE, EGG], [SHOVEL, STICK, EGG, STONE], [SHOVEL, STONE, STICK, EGG], [SHOVEL, STONE, EGG, STICK], [SHOVEL, EGG, STICK, STONE], [SHOVEL, EGG, STONE, STICK]]
Printing inventory:
[[STICK, STONE, EGG], [STICK, EGG, STONE], [STONE, STICK, EGG], [STONE, EGG, STICK], [EGG, STICK, STONE], [EGG, STONE, STICK]]
あなたの質問で何か見逃した場合はコメントしてください。これは興味深い問題でした。