在Java中优化If- else if- else语句

Question

在做乐透检查程序时，约束之一是 不使用循环 或 数据结构，例如数组，列表等< / strong> 我编写了以下代码，以检查用户给出的3个条目（ draw1，draw2，draw3 ）是否等于所生成的7个随机数中的任何一个通过程序（ random1，random2，random3，... ）。

if (random1==draw1 || random2==draw1 || random3==draw1 || random4==draw1|| random5==draw1
    || random6==draw1 || random7==draw1)
    {
        if(random1==draw2 || random2==draw2 || random3==draw2 || random4==draw2|| random5==draw2
        || random6==draw2 || random7==draw2)
        {
            if(random1==draw3 || random2==draw3 || random3==draw3 || random4==draw3|| random5==draw3
            || random6==draw3 || random7==draw3)
            {
                str = str +'\n' + "The following 3 matches were found:" +'\n'+ draw1 + " " + draw2
                + " " + draw3 ;
            }else
            {
                str = str + '\n' + "The following 2 matches were found:" + '\n' + draw1 + " " + draw2;
            }
        }else if (random1==draw3 || random2==draw3 || random3==draw3 || random4==draw3|| random5==draw3
        || random6==draw3 || random7==draw3)
        {
            str = str + '\n' + "The following 2 matches were found:" + '\n' + draw1 + " " + draw3 ;
        }
        else
        {
            str = str + '\n' + "The following 1 matches were found:" + '\n' + draw1;
        }
    }else if (random1==draw2 || random2==draw2 || random3==draw2 || random4==draw2|| random5==draw2
    || random6==draw2 || random7==draw2)
    {
        if(random1==draw3 || random2==draw3 || random3==draw3 || random4==draw3|| random5==draw3
        || random6==draw3 || random7==draw3)
        {
            str = str + '\n' + "The following 2 matches were found:" + '\n' + draw2 + " " + draw3;
        }
        else
        {
            str = str + '\n' + "The following 1 matches were found:" + '\n' + draw2;
        }
    }
    else if (random1==draw3 || random2==draw3 || random3==draw3 || random4==draw3|| random5==draw3
    || random6==draw3 || random7==draw3)
    {
        str = str + '\n' + "The following 1 matches were found:" + '\n' + draw3;
    }
    else
    {
        str = str + '\n' + "The following 0 matches were found:" ;
    }

如何进行优化，最重要的是优化只会增加可读性，还是会提高程序效率？

Answer 1

使用集，这将提高可读性。

    Set<Integer> luckyNumbers = new HashSet<>();
    //Add your numbers to the set
    //Integer i = ...
    //luckyNumbers.add(i);

    Set<Integer> drawNumbers = new HashSet<>();
    //Integer i = ...
    //drawNumbers.add(i);

    Set<Integer> matchNumbers = new HashSet<>(luckyNumbers);
    matchNumbers.retainAll(drawNumbers);
    //In matchNumbers will be the intersection of the previous sets.
    //There you can get the size of the intersection set or its content to show the
    //matches

如果要在此部分使用循环，可以执行以下操作：

System.out.println("Number of matches: " + matchNumbers.size());

        for(Integer matchNumber : matchNumbers){

            System.out.println("Match number: " + matchNumber);

        }

Answer 2

尝试一下。

static boolean equalsAny(int base, int... comparisons) {
    for (int c : comparisons)
        if (base == c)
            return true;
    return false;
}

您可以重写

 if (random1 == draw1 || random2 == draw1 || random3 == draw1 || random4 == draw1 || random5 == draw1
     || random6 == draw1 || random7 == draw1) {

到

if (equalsAny(draw1, random1, random2, random3, random4, random5, random6, random7)) {