求一个C#排列算法，要得到具体的数据，不是一共多少个
有M位数据，每位只能是1或者0，我把X个1入进去。列出所有组合数据。M>=2.0<X<=M;
如：M=2，X=1 结果如下：
1 0
0 1
如：M=X=2，结果如下：
1 1
我要得到这些数据。请问怎么用C#实现方法
public string[] ZhuHe(int M,int X);
把结果返回到一个数组里。请问方法怎么实现。谢谢。
[解决办法]
public class PermutationAndCombination<T>
{
/// <summary>
/// 交换两个变量
/// </summary>
/// <param name="a">变量1</param>
/// <param name="b">变量2</param>
public static void Swap(ref T a, ref T b)
{
T temp = a;
a = b;
b = temp;
}
/// <summary>
/// 递归算法求数组的组合(私有成员)
/// </summary>
/// <param name="list">返回的范型</param>
/// <param name="t">所求数组</param>
/// <param name="n">辅助变量</param>
/// <param name="m">辅助变量</param>
/// <param name="b">辅助数组</param>
/// <param name="M">辅助变量M</param>
private static void GetCombination(ref List<T[]> list, T[] t, int n, int m, int[] b, int M)
{
for (int i = n; i >= m; i--)
{
b[m - 1] = i - 1;
if (m > 1)
{
GetCombination(ref list, t, i - 1, m - 1, b, M);
}
else
{
if (list == null)
{
list = new List<T[]>();
}
T[] temp = new T[M];
for (int j = 0; j < b.Length; j++)
{
temp[j] = t[b[j]];
}
list.Add(temp);
}
}
}
/// <summary>
/// 递归算法求排列(私有成员)
/// </summary>
/// <param name="list">返回的列表</param>
/// <param name="t">所求数组</param>
/// <param name="startIndex">起始标号</param>
/// <param name="endIndex">结束标号</param>
private static void GetPermutation(ref List<T[]> list, T[] t, int startIndex, int endIndex)
{
if (startIndex == endIndex)
{
if (list == null)
{
list = new List<T[]>();
}
T[] temp = new T[t.Length];
t.CopyTo(temp, 0);
list.Add(temp);
}
else
{
for (int i = startIndex; i <= endIndex; i++)
{
Swap(ref t[startIndex], ref t[i]);
GetPermutation(ref list, t, startIndex + 1, endIndex);
Swap(ref t[startIndex], ref t[i]);
}
}
}
/// <summary>
/// 求从起始标号到结束标号的排列，其余元素不变
/// </summary>
/// <param name="t">所求数组</param>
/// <param name="startIndex">起始标号</param>
/// <param name="endIndex">结束标号</param>
/// <returns>从起始标号到结束标号排列的范型</returns>
public static List<T[]> GetPermutation(T[] t, int startIndex, int endIndex)
{
if (startIndex < 0
[解决办法]
endIndex > t.Length - 1)
{
return null;
}
List<T[]> list = new List<T[]>();
GetPermutation(ref list, t, startIndex, endIndex);
return list;
}
/// <summary>
/// 返回数组所有元素的全排列
/// </summary>
/// <param name="t">所求数组</param>
/// <returns>全排列的范型</returns>
public static List<T[]> GetPermutation(T[] t)
{
return GetPermutation(t, 0, t.Length - 1);
}
/// <summary>
/// 求数组中n个元素的排列
/// </summary>
/// <param name="t">所求数组</param>
/// <param name="n">元素个数</param>
/// <returns>数组中n个元素的排列</returns>
public static List<T[]> GetPermutation(T[] t, int n)
{
if (n > t.Length)
{
return null;
}
List<T[]> list = new List<T[]>();
List<T[]> c = GetCombination(t, n);
for (int i = 0; i < c.Count; i++)
{
List<T[]> l = new List<T[]>();
GetPermutation(ref l, c[i], 0, n - 1);
list.AddRange(l);
}
return list;
}
/// <summary>
/// 求数组中n个元素的组合
/// </summary>
/// <param name="t">所求数组</param>
/// <param name="n">元素个数</param>
/// <returns>数组中n个元素的组合的范型</returns>
public static List<T[]> GetCombination(T[] t, int n)
{
if (t.Length < n)
{
return null;
}
int[] temp = new int[n];
List<T[]> list = new List<T[]>();
GetCombination(ref list, t, t.Length, n, temp, n);
return list;
}
}
private string[] ZhuHe(int M, int X)
{
//if (M == X) 可以直接返回
List<string> list = new List<string>();
int max = GetMax(M, X);
int min = GetMin(M, X);
for (int i = min; i <= max; i++)
{
//根据需要进行左边补0
string value = Convert.ToString(i, 2);
if (value.Replace("0", "").Length == 5)
list.Add(value);
}
return list.ToArray();
}
/// <summary>
/// 获取M位数中存在X个1时表示的最大二进制数
/// </summary>
/// <param name="M"></param>
/// <param name="X"></param>
/// <returns></returns>
private int GetMax(int M, int X)
{
string str = "";
for (int i = 0; i < M; i++)
{
str += (i < X) ? "1" : "0";
}
return Convert.ToInt32(str, 2);
}
/// <summary>
/// 获取M位数中存在X个1时表示的最小二进制数
/// </summary>
/// <param name="M"></param>
/// <param name="X"></param>
/// <returns></returns>
private int GetMin(int M, int X)
{
string str = "";
for (int i = 0; i < M; i++)
{
str = (i < X) ? "1" : "0" + str;
}
return Convert.ToInt32(str, 2);
}
public static string[] Zuhe(int m, int x)
{
if (x < 0)
{
return new string[0];
}
if (m == x)
{
return new[] {new string('1', m)}; // m '1's
}
var z0 = Zuhe(m - 1, x);
var z1 = Zuhe(m - 1, x - 1);
var res = new string[z0.Length+z1.Length];
int i = 0;
foreach (var s in z0)
{
res[i++] = '0' + s; // can optimize with StringBuilder, same below
}
foreach (var s in z1)
{
res[i++] = '1' + s;
}
return res;
}
