java - 如何统计彩票中每个开奖号码的金额并将其输出到列表中？

Question

我正在编写这个小彩票应用程序。现在的计划是，计算每次彩票迭代期间每个号码被抽取的频率，并将其存储在某个地方。我的猜测是，我需要使用 HashMap，它有 6 个键，并且每次绘制相应的键编号时，值都会增加 1。但我该如何实现这个目标呢？到目前为止我的代码:

public void numberCreator()
{
    // creating and initializing a Random generator
   Random rand = new Random();
   // A HashMap to store the numbers picked. 
   HashMap hashMap = new HashMap();
   // A TreeMap to sort the numbers picked.
   TreeMap treeMap = new TreeMap();

    // creating an ArrayList which will store the pool of availbale Numbers
    List<Integer>numPool = new ArrayList<Integer>();

    for (int i=1; i<50; i++){
    // add the available Numbers to the pool
    numPool.add(i); 
    hashMap.put(nums[i], 0);
    }

    // array to store the lotto numbers
    int [] nums = new int [6];

    for (int i =0; i < nums.length; i++){
    int numPoolIndex = rand.nextInt(numPool.size());
    nums[i] = numPool.get(numPoolIndex);

    // check how often a number has been called and store the new amount in the Map
    int counter =  hashMap.get

    numPool.remove(numPoolIndex);
    }

    System.out.println(Arrays.toString(nums));

    }

也许有人可以告诉我我的想法是否正确，甚至如何正确实现 map ？

Answer 1

HashMap，或者任何类型的映射，在这里都太复杂了。计算数字出现次数所需的只是一个数组。

假设你有 49 个可能的数字，声明一个数组:

int counts = new int[49];
Arrays.fill(counts,0);

然后对于每次抽奖:

int drawnumbers[6]; // put the numbers for this draw in the array
for (int i=0;i<6;++i) {
  counts[drawnumbers[i]-1]++;
}

最后打印结果:

for (int i=0;i<49;++i) {
  System.out.println("Number "+(i+1)+" occurred "+counts[i]+" times.");
}