//-------------------- 全排列和组合排列
class B_Test
{
/// <summary>
/// 对数组进行组合操作，选取selectCount个元素进行组合
/// </summary>
/// <param name="lsArray">即将进行组合操作的数组</param>
/// <param name="selectCount">选取的元素的个数</param>
public static void C(List<string> lsArray, int selectCount)
{
int totolcount = lsArray.Count;
int[] currectselect = new int[selectCount];
int last = selectCount - 1;
for (int i = 0; i < selectCount; i++)
{
currectselect[i] = i;
}
while (true)
{
for (int i = 0; i < selectCount; i++)
{
Console.Write(" {0} ", lsArray[currectselect[i]]);
}
Console.WriteLine();
if (currectselect[last] < totolcount - 1)
{
currectselect[last]++;
}
else
{
int pos = last;
while (pos > 0 && currectselect[pos - 1] == currectselect[pos] - 1)
{
pos--;
}
if (pos == 0) return;
currectselect[pos - 1]++;
for (int i = pos; i < selectCount; i++)
{
currectselect[i] = currectselect[i - 1] + 1;
}
}
}
}
#region
/// <summary>
/// 返回组合值（思想是用currectselect记录取的lsArray的每个数对应数组的位置，先把currectselect最后一数加到isarry.cout，接着是倒数第二个加到小于倒数第一个，依次类推知道第0位）
/// </summary>
/// <param name="lsArray">即将进行组合操作的数组</param>
/// <param name="selectCount">选取的元素的个数</param>
public static List<string> D(List<string> lsArray, int selectCount)
{
List<string> list_return=new List<string>();
int totolcount = lsArray.Count;
int[] currectselect = new int[selectCount];
int last = selectCount - 1;
for (int i = 0; i < selectCount; i++)
{
currectselect[i] = i;
}
while (true)
{
for (int i = 0; i < selectCount; i++)
{
list_return.Add(lsArray[currectselect[i]]);
//Console.Write(" {0} ", lsArray[currectselect[i]]);
}
//Console.WriteLine();
if (currectselect[last] < totolcount - 1)
{
currectselect[last]++;
}
else
{
int pos = last;
while (pos > 0 && currectselect[pos - 1] == currectselect[pos] - 1)
{
pos--;
}
if (pos == 0) break;
currectselect[pos - 1]++;
for (int i = pos; i < selectCount; i++)
{
currectselect[i] = currectselect[i - 1] + 1;
}
}
}
return list_return;
}
/// <summary>
/// list 排列的数组的次序
/// </summary>
/// <param name="list">排列数组</param>
/// <param name="selectCount">全排列的个数</param>
public static void PN(Func<List<string>, int, List<string>> list,List<string> list_input, int selectCount)
{
List<string> list_get = new List<string>();
list_get = list(list_input,selectCount);
List<string> sub_list = new List<string>();
foreach (string lis in list_get)
{
sub_list.Add(lis);
if(sub_list.Count==selectCount)
{
A(sub_list,0,selectCount-1);
sub_list.Clear();
}
}
Console.Write("----------p/n--------");
Console.WriteLine();
}
#endregion
/// <summary>
/// 对数组进行全排列(用全排列的递归思想)
/// </summary>
/// <param name="lsArray">要进行全排列的数组</param>
/// <param name="begin">进行全排列的开始下标</param>
/// <param name="end">进行全排列的结束下标</param>
public static void A(List<string> lsArray, int begin, int end)
{
if (begin == end)
{
for (int i = 0; i <= end; i++)
Console.Write(" {0} ", lsArray[i]);
Console.WriteLine();
}
for (int i = begin; i <= end; i++)
{
Swap(lsArray, begin, i);
A(lsArray, begin + 1, end);
Swap(lsArray, begin, i);
}
}
/// <summary>
/// 交换数组中的下标为x,y的值
/// </summary>
/// <param name="lsArray">该数组</param>
/// <param name="x"></param>
/// <param name="y"></param>
public static void Swap(List<string> lsArray, int x, int y)
{
string t = lsArray[x];
lsArray[x] = lsArray[y];
lsArray[y] = t;
}
}