使用循环算法从多个列表中选择数据的有效方法 [英] Efficient way to choose data from several Lists with round robin algorithm

问题描述

从几个列表中，我需要使用循环算法选择数据，以创建一个包含所有其他值的单个结果列表.

From several lists I need to create a single result list with the values of all of the others, by choosing the data with a round robin algorithm.

list1 = val1_1,val1_2 .. 
list2 = val2_1,val2_2 .. 
list3 = val3_1,val3_2 ..
//rr choosing
result = val1_1,val2_1,val3_1,val1_2,val2_2,val3_2,val1_3...

每个列表中的值数可能不同.我该怎么办?

The number of values in each list may be different. How can I do this?

推荐答案

您可以使用从各个列表派生的 Iterators 的 Queue .从队列中获取下一个迭代器，从迭代器中获取下一个元素，如果不为空，则将其添加回队列中.

You could use a Queue of Iterators derived from the individual lists. Get the next iterator from the queue, get the next element from the iterator, and add it back to the queue if it is not empty.

List<String> lst1 = new ArrayList<>(Arrays.asList("a", "b", "c"));
List<String> lst2 = new ArrayList<>(Arrays.asList("A", "B"));
List<String> lst3 = new ArrayList<>(Arrays.asList("1", "2", "3", "4"));

Queue<Iterator<String>> iters = new LinkedList<>(Stream.of(lst1, lst2, lst3)
        .map(List::iterator).collect(Collectors.toList()));

List<String> result = new LinkedList<>();
while (! iters.isEmpty()) {
    Iterator<String> iter = iters.poll();
    if (iter.hasNext()) {
        result.add(iter.next());
        iters.add(iter);
    }
}
System.out.println(result); // [a, A, 1, b, B, 2, c, 3, 4]

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