字符串的排列

题目描述

输入一个字符串,按字典序打印出该字符串中字符的所有排列。例如输入字符串abc,则打印出由字符a,b,c所能排列出来的所有字符串abc,acb,bac,bca,cab和cba。  

输入描述:

输入一个字符串,长度不超过9(可能有字符重复),字符只包括大小写字母。

import java.util.ArrayList;
import java.util.Collections;
public class Solution {
    	public ArrayList<String> Permutation(String str) {
		ArrayList<String> result = new ArrayList<String>();
		if (str.length() == 0 || str == null) {
			return result;
		}
		char[] in = str.toCharArray();
		Permutation(result, in, 0, in.length);
		Collections.sort(result);
		return result;

	}

	public static void Permutation(ArrayList<String> list, char[] in,
			int start, int end) {
		if (start == end - 1) {
			String result = new String(in);
			if (!list.contains(result))
				list.add(result);
			return;
		}
		for (int i = start; i < end; i++) {
			char temp1 = in[start];
			char temp2 = in[i];
			in[start] = in[i];
			in[i] = temp1;
			Permutation(list, in, start + 1, end);
			in[start] = temp1;
			in[i] = temp2;
		}
	}
}