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

这使用了一点bitmagic(你已经通过在一个整数中保存两个比特信息(low/high & attack/block)来做到这一点):

我没有运行,只是在这里输入,请仔细检查。这个想法肯定有效。 编辑:现在对每个输入进行测试,工作正常。

public int fightMath(int one, int two) {
    if(one<2 && two<2){ //both players blocking
        return 0; // nobody hits
    }else if(one>1 && two>1){ //both players attacking
        return 3; // both hit
    }else{ // some of them attack, other one blocks
        int different_height = (one ^ two) & 1; // is 0 if they are both going for the same height - i.e. blocker wins, and 1 if height is different, thus attacker wins
        int attacker = one>1?1:0; // is 1 if one is the attacker, two is the blocker, and 0 if one is the blocker, two is the attacker
        return (attacker ^ different_height) + 1;
    }
}

或者我应该建议把这两个信息分离成单独的变量? 主要基于上面这样的位操作的代码通常很难维护。

其他回答

您可以创建包含结果的矩阵

int[][] results = {{0, 0, 1, 2}, {0, 0, 2, 1},{2, 1, 3, 3},{2, 1, 3, 3}};

当你想要获得价值时,你就会使用

public int fightMath(int one, int two) {
  return this.results[one][two]; 
}

Other people have already suggested my initial idea, the matrix method, but in addition to consolidating the if statements you can avoid some of what you have by making sure the arguments supplied are in the expected range and by using in-place returns (some coding standards I've seen enforce one-point-of-exit for functions, but I've found that multiple returns are very useful for avoiding arrow coding and with the prevalence of exceptions in Java there's not much point in strictly enforcing such a rule anyway as any uncaught exception thrown inside the method is a possible point of exit anyway). Nesting switch statements is a possibility, but for the small range of values you're checking here I find if statements to be more compact and not likely to result in much of a performance difference, especially if your program is turn-based rather than real-time.

public int fightMath(int one, int two) {
    if (one > 3 || one < 0 || two > 3 || two < 0) {
        throw new IllegalArgumentException("Result is undefined for arguments outside the range [0, 3]");
    }

    if (one <= 1) {
        if (two <= 1) return 0;
        if (two - one == 2) return 1;
        return 2; // two can only be 3 here, no need for an explicit conditional
    }

    // one >= 2
    if (two >= 2) return 3;
    if (two == 1) return 1;
    return 2; // two can only be 0 here
}

由于部分输入->结果映射的不规则性,这最终会导致可读性较差。我更喜欢矩阵风格,因为它的简单性和你如何设置矩阵在视觉上有意义(尽管这在一定程度上受到我对Karnaugh地图的记忆的影响):

int[][] results = {{0, 0, 1, 2},
                   {0, 0, 2, 1},
                   {2, 1, 3, 3},
                   {2, 1, 3, 3}};

更新:鉴于您提到了阻塞/命中,这里对函数进行了更彻底的更改,将属性/属性保存枚举类型用于输入和结果,并对结果进行了一些修改以考虑阻塞,这应该会产生一个更可读的函数。

enum MoveType {
    ATTACK,
    BLOCK;
}

enum MoveHeight {
    HIGH,
    LOW;
}

enum Move {
    // Enum members can have properties/attributes/data members of their own
    ATTACK_HIGH(MoveType.ATTACK, MoveHeight.HIGH),
    ATTACK_LOW(MoveType.ATTACK, MoveHeight.LOW),
    BLOCK_HIGH(MoveType.BLOCK, MoveHeight.HIGH),
    BLOCK_LOW(MoveType.BLOCK, MoveHeight.LOW);

    public final MoveType type;
    public final MoveHeight height;

    private Move(MoveType type, MoveHeight height) {
        this.type = type;
        this.height = height;
    }

    /** Makes the attack checks later on simpler. */
    public boolean isAttack() {
        return this.type == MoveType.ATTACK;
    }
}

enum LandedHit {
    NEITHER,
    PLAYER_ONE,
    PLAYER_TWO,
    BOTH;
}

LandedHit fightMath(Move one, Move two) {
    // One is an attack, the other is a block
    if (one.type != two.type) {
        // attack at some height gets blocked by block at same height
        if (one.height == two.height) return LandedHit.NEITHER;

        // Either player 1 attacked or player 2 attacked; whoever did
        // lands a hit
        if (one.isAttack()) return LandedHit.PLAYER_ONE;
        return LandedHit.PLAYER_TWO;
    }

    // both attack
    if (one.isAttack()) return LandedHit.BOTH;

    // both block
    return LandedHit.NEITHER;
}

You don't even have to change the function itself if you want to add blocks/attacks of more heights, just the enums; adding additional types of moves will probably require modification of the function, though. Also, EnumSets might be more extensible than using extra enums as properties of the main enum, e.g. EnumSet<Move> attacks = EnumSet.of(Move.ATTACK_HIGH, Move.ATTACK_LOW, ...); and then attacks.contains(move) rather than move.type == MoveType.ATTACK, though using EnumSets will probably be slightly slower than direct equals checks.


对于一个成功的块产生一个计数器的情况,您可以替换if (one。height == 2 .height)返回LandedHit.NEITHER;与

if (one.height == two.height) {
    // Successful block results in a counter against the attacker
    if (one.isAttack()) return LandedHit.PLAYER_TWO;
    return LandedHit.PLAYER_ONE;
}

另外,使用三元运算符(boolean_expression ?result_if_true: result_if_false)可以使代码更紧凑(例如,前面块中的代码将变成return one.isAttack() ?LandedHit。PLAYER_TWO: LandedHit.PLAYER_ONE;),但这可能会导致更难阅读的一行代码,所以我不建议在更复杂的分支中使用它。

((two&2)*(1+((one^two)&1))+(one&2)*(2-((one^two)&1)))/2

看看我们都知道些什么

1:你的答案对于参与人1 P1和参与人2 P2是对称的。这对于格斗游戏来说很有意义,但你也可以利用它来完善你的逻辑。

2:3拍0拍2拍1拍3。这些情况中唯一不包括的情况是0对1和2对3的组合。换句话说,唯一的胜利表是这样的:0击败2,1击败3,2击败1,3击败0。

3:如果0/1人对位,则平局无命中,但如果2/3人对位,则双方均命中

首先,让我们构建一个单向函数,告诉我们是否赢了:

// returns whether we beat our opponent
public boolean doesBeat(int attacker, int defender) {
  int[] beats = {2, 3, 1, 0};
  return defender == beats[attacker];
}

然后我们可以使用这个函数来组合最终的结果:

// returns the overall fight result
// bit 0 = one hits
// bit 1 = two hits
public int fightMath(int one, int two)
{
  // Check to see whether either has an outright winning combo
  if (doesBeat(one, two))
    return 1;

  if (doesBeat(two, one))
    return 2;

  // If both have 0/1 then its hitless draw but if both have 2/3 then they both hit.
  // We can check this by seeing whether the second bit is set and we need only check
  // one's value as combinations where they don't both have 0/1 or 2/3 have already
  // been dealt with 
  return (one & 2) ? 3 : 0;
}

虽然这可以说比许多答案中提供的查找表更复杂,而且可能更慢,但我相信这是一种更好的方法,因为它实际上封装了代码的逻辑,并向阅读您代码的任何人描述它。我认为这是一个更好的实现。

(这是一段时间以来,我做任何Java,所以抱歉,如果语法错误,希望它仍然是可理解的,如果我有一点错误)

顺便说一下,0-3显然意味着什么;它们不是任意的值,所以给它们命名会有帮助。

如果你无法想出一个公式,你可以使用一个表格来描述有限的结果:

final int[][] result = new int[][] {
  { 0, 0, 1, 2 },
  { 0, 0, 2, 1 },
  { 2, 1, 3, 3 },
  { 1, 2, 3, 3 }
};
return result[one][two];