《剑指offer—面试题38:字符串的排序》
注明:仅个人学习笔记
https://www.nowcoder.com/profile/631996/codeBookDetail?submissionId=1512262
https://www.cnblogs.com/liang1101/p/6376210.html
import java.util.ArrayList;
import java.util.Iterator;
import java.util.TreeSet;
/**
*
*
* 字符串的排列 输入一个字符串,打印出该字符串的所有排列 例如输入abc,打印出来,abc,acb,bac,bca,cba,cab
*
*/
public class StringRank38
{
public ArrayList Permutation(String str)
{
ArrayList result = new ArrayList();
if (str == null || str.length() == 0)
{
return result;
}
char[] chars = str.toCharArray();
TreeSet<String> temp = new TreeSet<String>();// 用该容器,避免重复数据
Permutation(chars, 0, temp);
result.addAll(temp);
return result;
}
public void Permutation(char[] chars, int begin, TreeSet<String> result)
{
if (chars == null || chars.length == 0 || begin < 0 || begin > chars.length - 1)
{
return;
}
if (begin == chars.length - 1)
{
result.add(String.valueOf(chars));
} else
{
for (int i = begin; i < chars.length; i++)
{
swap(chars, begin, i);
Permutation(chars, begin + 1, result);
swap(chars, begin, i);// 还原当前chars
}
}
}
private void swap(char[] x, int a, int b)
{
// TODO Auto-generated method stub
char t = x[a];
x[a] = x[b];
x[b] = t;
}
public static void main(String[] args)
{
String str = "abc";
StringRank38 sk = new StringRank38();
ArrayList<String> list = sk.Permutation(str);
Iterator<String> iter = list.iterator();
for (; iter.hasNext();)
{
System.out.println(iter.next());
}
}
}