Java:交错两个基于整数的数组列表 ->好方法? [英] Java: Interleave two integer based arraylists -> good approach?

问题描述

家庭作业:寻找更好的策略或方法，而不是完整的代码.

我在两种情况下得到了两个整数数组:

I'v got two arrayLists of integers under two conditions:

1. 第一个列表比第二个大
2. 第二个列表比第一个大

我的目标是在两种情况下将 list2 的元素交错到 list1 中.我已经创建了一个方法来做到这一点，但我觉得我可以做得更好.

My goal was to interleave elements of list2, into list1 under both conditions. I've created a method that does this, but I feel like I could be doing something better.

这里是条件 1 的预期结果.注意，在 list2 的元素耗尽后，我们将 list1 的元素留在原地:

Here is the expected result for condition 1. Note that after the elements of list2 are exhausted, we leave the elements of list1 in place:

list1: [10, 20, 30, 40, 50, 60, 70]
list2: [4, 5, 6, 7]
Combined: [10, 4, 20, 5, 30, 6, 40, 7, 50, 60, 70]

这里是条件 2 的预期结果.由于 list2 有更多元素，我们在 list1 用完后将这些元素附加到 list1:

Here is the expected result for condition 2. Since list2 has more elements, we append these elements to list1 after list1 is exhausted:

list1: [10, 20, 30, 40]
list2: [4, 5, 6, 7, 8, 9, 10, 11]
Combined: [10, 4, 20, 5, 30, 6, 40, 7, 8, 9, 10, 11]

我的代码使用 if-else 语句来处理这两个条件.然后我使用迭代器遍历 list2 的元素并将它们插入到 list1 中.

My code uses an if-else statement to process both conditions. I then use an iterator to go through elements of list2 and insert them in list1.

public static void main(String[] Args)
{
    ArrayList<Integer> numbers = new ArrayList<Integer>();
    numbers.add(10);
    numbers.add(20);
    numbers.add(30);
    numbers.add(40);
    //numbers.add(50);
    //numbers.add(60);
    //numbers.add(70);

    ArrayList<Integer> numbers2 = new ArrayList<Integer>();

    numbers2.add(4);
    numbers2.add(5);
    numbers2.add(6);
    numbers2.add(7);
    numbers2.add(8);
    numbers2.add(9);
    numbers2.add(10);
    numbers2.add(11);

    System.out.println("list1: " + numbers);
    System.out.println("list2: " + numbers2);

    interleave(numbers, numbers2);

    System.out.println();
    System.out.println("Combined: " + numbers);
}

public static void interleave(ArrayList<Integer> list1, ArrayList<Integer> list2)
{
    //obtain an iterator for the collection
    Iterator<Integer> itr2 = list2.iterator();

    //loop counter
    int count = 1;

    //handle based on initial size of lists
    if(list1.size() >= list2.size())
    {
       //loop through the first array and add elements from list 2 after each element
       while(itr2.hasNext())
       {
           //insert elements from list2
           list1.add(count, itr2.next());

           //make sure elements are getting added at 1, 3, 5, 7, 9, etc
           count = count + 2;
       }
    }
    else if(list1.size() < list2.size())
    {
       //loop through the first array and add elements from list 2 after each element
       while(itr2.hasNext())
       {
           if(count <= list1.size())
           {
               //insert elements from list2
               list1.add(count, itr2.next());

               //make sure elements are getting added at 1, 3, 5, 7, 9, etc
               count = count + 2;
           }
           else
           {
               //fill in the remainder of the elements from list2 to list1
               list1.add(itr2.next());
           }
       }
    }
}

推荐答案

您喜欢这个解决方案吗?

Do you like this solution?

public static void main(final String[] args) {
    ArrayList<Integer> numbers = new ArrayList<Integer>();
    numbers.add(10); numbers.add(20); numbers.add(30); numbers.add(40);
    //numbers.add(50); numbers.add(60); numbers.add(70);

    ArrayList<Integer> numbers2 = new ArrayList<Integer>();
    numbers2.add(4); numbers2.add(5); numbers2.add(6); numbers2.add(7);
    numbers2.add(8); numbers2.add(9); numbers2.add(10); numbers2.add(11);

    System.out.println("list1: " + numbers);
    System.out.println("list2: " + numbers2);
    List<Integer> interleaved = interleave(numbers, numbers2);

    System.out.println("\nCombined: " + interleaved);
}

public static List<Integer> interleave(
    final List<Integer> list1,
    final List<Integer> list2
) {
    List<Integer> result
        = new ArrayList<Integer>(list1.size() + list2.size());

    Iterator<Integer> it1 = list1.iterator();
    Iterator<Integer> it2 = list2.iterator();
    while (it1.hasNext() || it2.hasNext()) {
        if (it1.hasNext()) {
            result.add(it1.next());
        }
        if (it2.hasNext()) {
            result.add(it2.next());
        }
    }
    return result;
}

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