高人请进，递归算法问题

[AuC]

对4个数进行排序 实现不同的排法？

[liu4545533]

我使用java实现的 算法出来了 改成.net也简单啦

package com.list;

import java.util.ArrayList;

public class ListAll {
	public static void main(String[] args)
	{
		ArrayList str=new ArrayList();
		str.add("a");
		str.add("b");
		str.add("c");
//		str.add("d");
//		str.add("e");
		for(int i=0;i<str.size();i++)
		{
			System.out.print(str.get(i).toString()+",");
		}
		System.out.println("的排列为：");
		ListAll all=new ListAll();
		ArrayList str1=all.getArry(str);
		for(int i=0;i<str1.size();i++)
		{
			System.out.println(str1.get(i).toString());
		}
		
	}
	ArrayList getArry(ArrayList str)
	{
		if(str.size()==1)
		{
			return str;
		}
		else
		{
			ArrayList result=new ArrayList();
			String temp= str.get(0).toString();
			//String[] temp1=new String[str.length-1];
			ArrayList temp1=new ArrayList();
			for(int i=1;i<str.size();i++)
			{
				temp1.add(str.get(i));
			}
			ArrayList temp2=getArry(temp1);
			for(int i=0;i<temp2.size();i++)
			{
				int index=temp2.get(i).toString().indexOf(temp);
				if(index==-1)
				{
					for(int j=0;j<=temp2.get(i).toString().length();j++)
					{
						StringBuffer s=new StringBuffer((temp2.get(i)).toString());
						String ss=s.insert(j, temp).toString();
						result.add(ss);
					}
				}
			}
			return result;
		}
	}
}

[tabbycat]

List<T>提供Sort方法的
有个委托的重载，可以使用自定义排序规则

[cppfaq]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace perm
{
    internal class Program
    {
        private static void permlist(int[] listdata, int k, int m)
        {
            if (k == m)


            {
                for (int i = 0; i <= m; i++) System.Console.Write(listdata[i]);
                Console.WriteLine();
            }
            else
                for (int i = k; i <= m; i++)


                {
                    Swap(ref listdata[k], ref listdata[i]);
                    permlist(listdata, k + 1, m);
                    Swap(ref listdata[k], ref listdata[i]);
                }
        }


        private static void Swap(ref int a, ref int b)
        {
            int temp = a;
            a = b;
            b = temp;
        }

        private static void Main(string[] args)
        {
            int[] listdata = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
            permlist(listdata, 0, 3);
            Console.ReadLine();
        }
    }
}

[zzxap]

[code=C#]

//快速排序
class QuickSorter
{
private void swap(ref int l, ref int r)
{
int temp;
temp = l;
l = r;
r = temp;
}
public void Sort(int[] list, int low, int high)
{
int pivot;//存储分支点
int l, r;
int mid;
if (high <= low)
return;
else if (high == low + 1)
{
if (list[low] > list[high])
swap(ref list[low], ref list[high]);
return;
}
mid = (low + high) >> 1;
pivot = list[mid];
swap(ref list[low], ref list[mid]);
l = low + 1;
r = high;
do
{
while (l <= r && list[l] < pivot)
l++;
while (list[r] >= pivot)
r--;
if (l < r)
swap(ref list[l], ref list[r]);
} while (l < r);
list[low] = list[r];
list[r] = pivot;
if (low + 1 < r)
Sort(list, low, r - 1);
if (r + 1 < high)
Sort(list, r + 1, high);
}



static void Main(string[] args)
{
int[] iArrary = new int[] {34, 75, 33, 47 };
QuickSorter q = new QuickSorter();
q.Sort(iArrary, 0, 13);
for (int m = 0; m <= 13; m++)
Console.WriteLine("{0}", iArrary[m]);
}
}
[/CODE]

[zzxap]

最简单的array.sort()

[zzxap]

[code=C#]
//希尔排序
public class ShellSorter
{
public void Sort(int[] arr)
{
int inc;
for (inc = 1; inc <= arr.Length / 9; inc = 3 * inc + 1) ;
for (; inc > 0; inc /= 3)
{
for (int i = inc + 1; i <= arr.Length; i += inc)
{
int t = arr[i - 1];
int j = i;
while ((j > inc) && (arr[j - inc - 1] > t))
{
arr[j - 1] = arr[j - inc - 1];//交换数据
j -= inc;
}
arr[j - 1] = t;
}
}
}

static void Main(string[] args)
{
int[] array = new int[] {34, 75, 33, 47 };
ShellSorter s = new ShellSorter();
s.Sort(array);
foreach (int m in array)
Console.WriteLine("{0}", m);

}
}

[/CODE]

[AuC]

1楼和3楼的都不错

[AuC]

最主要的是都用了递归的思想