打印列表项

Question

List<string> list = new List<string>();    
        list.Add("A");
        list.Add("B");

List<string> list1 = new List<string>();    
        list.Add("a");
        list.Add("b");


    for (int i = 0; i < list.Count; i++)
    {
        // print another list items.
        for (int j = 0; j < list1.Count; j++)
        {
            Console.WriteLine("/" + list[i] + "/" + list1[j]);
        }

    }

我想像这样编码string tmpS =+ list[i];加入下一个列表项togeter.

然后打印 tmpS

但编译错误CS0023:运算符'+'不能应用于'string'类型的操作数.

如何打印下面的所有项目.(任何种类都可以)

A A Ab Aab Aba AB ABa ABb ABab ABba B Ba Bb Bab Bba

(大写号码没有交换.小字符应该被交换.并且始终跟随大写号码附加小字符.)

Answer 1

这让我很长一段时间没有研究纯算法问题了！

这个程序应该可以解决这个问题：

class Program
{
    static void Main(string[] args)
    {
        List<string> uppers = new List<string>();
        uppers.Add("A");
        uppers.Add("B");

        List<string> lowers = new List<string>();
        lowers.Add("a");
        lowers.Add("b");

        List<string> combinedUppers = GetCombinedItems(uppers);
        List<string> combinedLowers = GetCombinedItems(lowers);
        List<string> combinedUppersLowers = GetCombinedList(combinedUppers, combinedLowers);

        foreach (string combo in combinedUppersLowers)
        {
            Console.WriteLine(combo);
        }

        Console.Read();
    }

    static private List<string> GetCombinedItems(List<string> list)
    {
        List<string> combinedItems = new List<string>();

        for (int i = 0; i < list.Count; i++)
        {
            combinedItems.Add(list[i]);

            for (int j = 0; j < list.Count; j++)
            {
                if (list[i] != list[j])
                {
                    combinedItems.Add(String.Format("{0}{1}", list[i], list[j]));
                }
            }
        }

        return combinedItems;
    }

    static private List<string> GetCombinedList(List<string> list1, List<string> list2)
    {
        List<string> combinedList = new List<string>();

        for (int i = 0; i < list1.Count; i++)
        {
            combinedList.Add(list1[i]);

            for (int j = 0; j < list2.Count; j++)
            {
                combinedList.Add(String.Format("{0}{1}", list1[i], list2[j]));
            }
        }

        for (int i = 0; i < list2.Count; i++)
        {
            combinedList.Add(list2[i]);

            for (int j = 0; j < list1.Count; j++)
            {
                combinedList.Add(String.Format("{0}{1}", list2[i], list1[j]));
            }
        }

        return combinedList;
    }
}

问候。

该程序为您提供以下输出：

A Aa Aab Ab Aba AB ABa ABab ABb ABba B Ba Bab Bb Bba BA BAa BAab Bab BAba a aA aAB aB aBA ab abA abAB abB abBA b BA bAB bB bBA ba baA baAB baB baBA