如何在java中合并多个map的两个成员？ [英] How to merge two members of a multimap in java?

问题描述

我在java中编写了一个multimap，我想将这个map的两个成员相互合并。地图如下：

I have written a multimap in java and I want to merge two members of this map to each other. the map is as follow:

Map<Integer,Map<Integer,Integer>> groups = new HashMap<>();

例如，如果group [0]为0 => {0 = 1,1 = 10}且组[1]为1 => {0 = 2,1 = 3}，我想答案是1 => {0 = 2,1 = 3,2 = 1,3 = 10}。我怎么能这样做？



我尝试了什么：



我搜索过它，但我找不到合适的解决方案

for example if group[0] is 0 => {0=1, 1=10} and group[1] is 1 => {0=2, 1=3}, I want the answer be 1 => {0=2, 1=3,2=1, 3=10}. how can I do this?

What I have tried:

I searched about it, but I could not find a proper solution

推荐答案

好吧，如果精彩的 Java 库不提供直接的解决方案，那么，你知道，你可能会使用开发技术，如迭代，条件语句等......

Well, if the wonderful Java libraries don't provide a direct solution, then, you know, you might resort to use development techniques, like iterations, conditional statements and the like...

Set <Integer> s0 = m.get(0).keySet();
Set <Integer> s1 = m.get(1).keySet();

Iterator <Integer> it0 = s0.iterator();
Iterator <Integer> it1 = s1.iterator();


Integer n0 = null;
Integer n1 = null;

Map <Integer, Integer> rm = new HashMap<Integer, Integer>();

int count = 1;

while (true)
{

  if ( n0 == null && it0.hasNext() )
    n0 = m.get(0).get(it0.next());

  if ( n1 == null && it1.hasNext() )
    n1 = m.get(1).get(it1.next());

  if ( n0 == null )
  {
    if (n1 == null)
      break;
    else
    {
      rm.put(count, n1);
      n1 = null;
      ++count;
    }
  }
  else
  {// here n0 != null
    if (n1 == null)
    {
      rm.put(count, n0);
      n0 = null;
      ++count;
    }
    else
    {
      if ( n0 < n1 )
      {
        rm.put(count, n0);
        n0 = null;
        ++count;
      }
      else
      {
        rm.put(count, n1);
        n1 = null;
        ++count;
      }
    }
  }

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