分组FizzBu​​zz数字

Question

我正在尝试在Java8中编写FizzBu​​zz问题。它工作正常，我得到了理想的输出。对于可以被＆＃34; 3＆＃34;整除的数字，它应该返回＆＃34; Fizz＆＃34;，对于可以被＆＃34; 5＆＃34;整除的数字，它应该返回＆＃34; Buzz＆＃34; ;对于可被两者整除的数字，它应该返回＆＃34; FizzBu​​zz＆＃34;。

如果我将值传递给＆＃34; 15＆＃34;它返回：

["1","2","Fizz","4","Buzz","Fizz","7","8","Fizz","Buzz","11","Fizz","13","14","FizzBuzz"]

现在，我陷入了困境。如果我将值传递为＆＃34; 15＆＃34;：

，我想获得如下输出

{"Fizz": [3, 6, 9, 12],"Buzz": [5, 10],"FizzBuzz": [15]}

我想通过Fizz，Buzz和FizzBu​​zz对这些数字进行分组。

这是我的代码：

public class FizzBuzzService {

private Map<Rule, String> ruleContainers = new HashMap();
private Set<Rule> rules  = new HashSet();

public FizzBuzzService(){
    addRule(i -> i % 15 == 0, "FizzBuzz");
    addRule(i -> i % 3 == 0, "Fizz");
    addRule(i -> i % 5 == 0, "Buzz");
}

public void addRule(Rule rule, String res) {
    rules.add(rule);
    ruleContainers.put(rule, res);
}

public String getValue(int i) {
    for (Rule rule : rules) {
        if (rule.apply(i)) {
            return ruleContainers.get(rule);
        }
    }
    return String.valueOf(i);
}

//then the origin code should be as follows:
public List<String> fizzBuzz(int n) {
     List<String> res = new ArrayList();
     for(int i = 1; i <= n; i++){
         res.add(getValue(i));
     }
     return res;
 }

interface Rule{
    boolean apply(int i);
}
}

如果有人能指导我，我真的很感激。感谢

Answer 1

这是使用流做的一种方法：

Map<String, List<String>> result = IntStream.rangeClosed(1, n)
    .filter(i -> i % 3 == 0 || i % 5 == 0)
    .boxed()
    .collect(Collectors.groupingBy(i ->
        i % 15 == 0 ? "FizzBuzz" :
        i %  3 == 0 ? "Fizz" : 
                      "Buzz"));

没有溪流：

Map<String, List<String>> result = new HashMap<>();
for (int i = 0; i < n; i++) {
    if (i % 3 == 0 || i % 5 == 0) {
        String key = i % 15 == 0 ? "FizzBuzz" :
                     i %  3 == 0 ? "Fizz" : 
                                   "Buzz";
        result.computeIfAbsent(key, k -> new ArrayList<>()).add(i);
    }
}

Answer 2

我会返回Map<String, List<Integer>>（使用LinkedHashMap代替HashMap，并且您的密钥将保留广告订单）为{{1}创建List<Integer>（s） }，fizz和buzz值。它可以在一个fizzbuzz方法中完成，例如，

static

Answer 3

PagingList

Answer 4

第1步：在号码上应用规则。

第2步：查找第一个匹配规则。

第3步：过滤未与任何规则匹配的元素。

第4步：按规则分组KeyWord

    public static void main(String[] args) {

        FizzBuzzService();
         Map<String, List<Integer>> fizzBuzzMap = IntStream.range(1, 31)
                  .mapToObj(number->applRule(number))
                  .filter(obj ->obj!=null)
                  .collect(Collectors.groupingBy(Entry::getKey,Collectors.mapping(Entry::getValue, Collectors.toList())));

         System.out.println("FizzBuzzMap : " + fizzBuzzMap);
    }

    private static SimpleEntry<String, Integer> applRule(Integer number) {

        Optional<Entry<Rule, String>> findFirst = ruleContainers.entrySet()
                                                                .stream()
                                                                .filter(rule -> rule.getKey().apply(number))
                                                                .findFirst();
        if (findFirst.isPresent()) {
            System.out.println("Number : " + number + " First Matching Rule : " +findFirst.get().getValue());
            return new SimpleEntry<>(findFirst.get().getValue(), number);
        }

        return null;
    }
}

    public static void FizzBuzzService(){
        addRule(i -> i % 3 == 0, "Fizz");
        addRule(i -> i % 5 == 0, "Buzz");
        addRule(i -> i % 15 == 0, "FizzBuzz");
    }

输出：

Number : 3 First Matching Rule : Fizz
Number : 5 First Matching Rule : Buzz
Number : 6 First Matching Rule : Fizz
Number : 9 First Matching Rule : Fizz
Number : 10 First Matching Rule : Buzz
Number : 12 First Matching Rule : Fizz
Number : 15 First Matching Rule : FizzBuzz
Number : 18 First Matching Rule : Fizz
Number : 20 First Matching Rule : Buzz
Number : 21 First Matching Rule : Fizz
Number : 24 First Matching Rule : Fizz
Number : 25 First Matching Rule : Buzz
Number : 27 First Matching Rule : Fizz
Number : 30 First Matching Rule : FizzBuzz
FizzBuzzMap : {FizzBuzz=[15, 30], Fizz=[3, 6, 9, 12, 18, 21, 24, 27], Buzz=[5, 10, 20, 25]}