下面的代码确实按照我需要的方式工作,但它很丑,过多或其他一些事情。我已经看了公式,并试图写一些解决方案,但我最终得到了类似数量的语句。

在这种情况下,是否有一种数学公式对我有益,或者是否可以接受16个if语句?

为了解释代码,这是一款基于同时回合制的游戏。两名玩家各有四个操作按钮,结果来自一个数组(0-3),但变量“1”和“2”可以赋值任何东西,如果这有帮助的话。结果是,0 =双方都不赢,1 = p1赢,2 = p2赢,3 =双方都赢。

public int fightMath(int one, int two) {

    if(one == 0 && two == 0) { result = 0; }
    else if(one == 0 && two == 1) { result = 0; }
    else if(one == 0 && two == 2) { result = 1; }
    else if(one == 0 && two == 3) { result = 2; }
    else if(one == 1 && two == 0) { result = 0; }
    else if(one == 1 && two == 1) { result = 0; }
    else if(one == 1 && two == 2) { result = 2; }
    else if(one == 1 && two == 3) { result = 1; }
    else if(one == 2 && two == 0) { result = 2; }
    else if(one == 2 && two == 1) { result = 1; }
    else if(one == 2 && two == 2) { result = 3; }
    else if(one == 2 && two == 3) { result = 3; }
    else if(one == 3 && two == 0) { result = 1; }
    else if(one == 3 && two == 1) { result = 2; }
    else if(one == 3 && two == 2) { result = 3; }
    else if(one == 3 && two == 3) { result = 3; }

    return result;
}

当前回答

下面是一个相当简洁的版本,类似于JAB的回应。这使用地图来存储哪个移动战胜其他移动。

public enum Result {
  P1Win, P2Win, BothWin, NeitherWin;
}

public enum Move {
  BLOCK_HIGH, BLOCK_LOW, ATTACK_HIGH, ATTACK_LOW;

  static final Map<Move, List<Move>> beats = new EnumMap<Move, List<Move>>(
      Move.class);

  static {
    beats.put(BLOCK_HIGH, new ArrayList<Move>());
    beats.put(BLOCK_LOW, new ArrayList<Move>());
    beats.put(ATTACK_HIGH, Arrays.asList(ATTACK_LOW, BLOCK_LOW));
    beats.put(ATTACK_LOW, Arrays.asList(ATTACK_HIGH, BLOCK_HIGH));
  }

  public static Result compare(Move p1Move, Move p2Move) {
    boolean p1Wins = beats.get(p1Move).contains(p2Move);
    boolean p2Wins = beats.get(p2Move).contains(p1Move);

    if (p1Wins) {
      return (p2Wins) ? Result.BothWin : Result.P1Win;
    }
    if (p2Wins) {
      return (p1Wins) ? Result.BothWin : Result.P2Win;
    }

    return Result.NeitherWin;
  }
} 

例子:

System.out.println(Move.compare(Move.ATTACK_HIGH, Move.BLOCK_LOW));

打印:

P1Win

其他回答

除了JAB之外,我不喜欢任何提出的解决方案。其他方法都不容易阅读代码和理解正在计算的内容。

以下是我如何编写这段代码——我只会c#,不懂Java,但你可以想象:

const bool t = true;
const bool f = false;
static readonly bool[,] attackResult = {
    { f, f, t, f }, 
    { f, f, f, t },
    { f, t, t, t },
    { t, f, t, t }
};
[Flags] enum HitResult 
{ 
    Neither = 0,
    PlayerOne = 1,
    PlayerTwo = 2,
    Both = PlayerOne | PlayerTwo
}
static HitResult ResolveAttack(int one, int two)
{
    return 
        (attackResult[one, two] ? HitResult.PlayerOne : HitResult.Neither) | 
        (attackResult[two, one] ? HitResult.PlayerTwo : HitResult.Neither);
}    

现在,这里计算的内容更加清楚了:这强调了我们正在计算谁受到了什么攻击,并返回两个结果。

然而,这可能会更好;布尔数组有点不透明。我喜欢表格查找方法,但我更倾向于以一种能够明确游戏语义的方式来编写它。也就是说,与其“攻击为零,防御为一,结果是没有命中”,不如找到一种方法,让代码更清楚地暗示“低踢攻击和低阻挡防御,结果是没有命中”。让代码反映游戏的业务逻辑。

我希望我正确理解了逻辑。比如:

public int fightMath (int one, int two)
{
    int oneHit = ((one == 3 && two != 1) || (one == 2 && two != 0)) ? 1 : 0;
    int twoHit = ((two == 3 && one != 1) || (two == 2 && one != 0)) ? 2 : 0;

    return oneHit+twoHit;
}

检查一个击中高或一个击中低不被阻止,同样的球员二。

编辑:算法不完全理解,“命中”奖励时,我没有意识到(谢谢elias):

public int fightMath (int one, int two)
{
    int oneAttack = ((one == 3 && two != 1) || (one == 2 && two != 0)) ? 1 : (one >= 2) ? 2 : 0;
    int twoAttack = ((two == 3 && one != 1) || (two == 2 && one != 0)) ? 2 : (two >= 2) ? 1 : 0;

    return oneAttack | twoAttack;
}

说实话,每个人都有自己的代码风格。我没想到性能会受到太大影响。如果您比使用开关箱版本更能理解这一点,那么请继续使用此版本。

您可以嵌套if语句,因此最后的if检查可能会略微提高性能,因为它不会经过那么多if语句。但是在你的java基础课程中,它可能不会有什么好处。

else if(one == 3 && two == 3) { result = 3; }

所以,与其…

if(one == 0 && two == 0) { result = 0; }
else if(one == 0 && two == 1) { result = 0; }
else if(one == 0 && two == 2) { result = 1; }
else if(one == 0 && two == 3) { result = 2; }

你会做……

if(one == 0) 
{ 
    if(two == 0) { result = 0; }
    else if(two == 1) { result = 0; }
    else if(two == 2) { result = 1; }
    else if(two == 3) { result = 2; }
}

按照你的喜好重新格式化。

这并没有使代码看起来更好,但我相信它可能会加快一点速度。

我个人喜欢级联三元运算符:

int result = condition1
    ? result1
    : condition2
    ? result2
    : condition3
    ? result3
    : resultElse;

但在你的情况下,你可以使用:

final int[] result = new int[/*16*/] {
    0, 0, 1, 2,
    0, 0, 2, 1,
    2, 1, 3, 3,
    1, 2, 3, 3
};

public int fightMath(int one, int two) {
    return result[one*4 + two];
}

或者,你可以注意到比特的模式:

one   two   result

section 1: higher bits are equals =>
both result bits are equals to that higher bits

00    00    00
00    01    00
01    00    00
01    01    00
10    10    11
10    11    11
11    10    11
11    11    11

section 2: higher bits are different =>
lower result bit is inverse of lower bit of 'two'
higher result bit is lower bit of 'two'

00    10    01
00    11    10
01    10    10
01    11    01
10    00    10
10    01    01
11    00    01
11    01    10

所以你可以使用魔法:

int fightMath(int one, int two) {
    int b1 = one & 2, b2 = two & 2;
    if (b1 == b2)
        return b1 | (b1 >> 1);

    b1 = two & 1;

    return (b1 << 1) | (~b1);
}

为什么不使用数组呢?

我将从头说起。我看到了一个模式,值从0到3,你想捕捉所有可能的值。这是你的桌子:

0 & 0 = 0
0 & 1 = 0
0 & 2 = 1
0 & 3 = 2
1 & 0 = 0
1 & 1 = 0
1 & 2 = 2
1 & 3 = 1
2 & 0 = 2
2 & 1 = 1
2 & 2 = 3
2 & 3 = 3
3 & 0 = 2
3 & 1 = 1
3 & 2 = 3
3 & 3 = 3

当我们查看相同的二进制表时,我们看到以下结果:

00 & 00 = 00
00 & 01 = 00
00 & 10 = 01
00 & 11 = 10
01 & 00 = 00
01 & 01 = 00
01 & 10 = 10
01 & 11 = 01
10 & 00 = 10
10 & 01 = 01
10 & 10 = 11
10 & 11 = 11
11 & 00 = 10
11 & 01 = 01
11 & 10 = 11
11 & 11 = 11

现在你可能已经看到了一些模式,但当我把值1和2结合起来时,我看到你使用了所有的值0000,0001,0010,.....1110和1111。现在让我们把值1和值2组合成一个4位整数。

0000 = 00
0001 = 00
0010 = 01
0011 = 10
0100 = 00
0101 = 00
0110 = 10
0111 = 01
1000 = 10
1001 = 01
1010 = 11
1011 = 11
1100 = 10
1101 = 01
1110 = 11
1111 = 11

当我们把它转换回十进制值时,我们看到一个非常可能的值数组,其中1和2的组合可以用作索引:

0 = 0
1 = 0
2 = 1
3 = 2
4 = 0
5 = 0
6 = 2
7 = 1
8 = 2
9 = 1
10 = 3
11 = 3
12 = 2
13 = 1
14 = 3
15 = 3

数组是{0,0,1,2,0,0,2,1,2,1,2,1,3,3,2,1,3,3,1,3,3},其中它的索引是1和2的组合。

我不是Java程序员,但你可以去掉所有的if语句,把它写下来,就像这样:

int[] myIntArray = {0, 0, 1, 2, 0, 0, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3};
result = myIntArray[one * 4 + two]; 

我不知道移位2是否比乘法快。但这值得一试。