九度 1369 字串的排列

package com.wangzhu.njupt;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.util.Arrays;

/**
 * 還有重複的字元陣列的全排列
 * 
 * @ClassName: Main1369
 * @Description: TODO
 * @author 王竹
 * @date 2014-10-5 下午3:04:55
 * 
 */
public class Main1369 {

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        //System.setIn(new FileInputStream("data.in"));
        StreamTokenizer in = new StreamTokenizer(new BufferedInputStream(
                System.in));
        while (in.nextToken() != StreamTokenizer.TT_EOF) {
            String str = in.sval;
            char[] buf = str.toCharArray();
            Arrays.sort(buf);
            int len = buf.length;
            boolean[] flagArr = new boolean[len];
            Arrays.fill(flagArr, true);
            char[] res = new char[len];
            dfs(0, len, buf, res, flagArr);
        }
    }

    /**
     * 輸入：<br/>
     * abc<br/>
     * BCA<br/>
     * 輸出：<br/>
     * abc<br/>
     * acb<br/>
     * bac<br/>
     * bca<br/>
     * cab<br/>
     * cba<br/>
     * ABC<br/>
     * ACB<br/>
     * BAC<br/>
     * BCA<br/>
     * CAB<br/>
     * CBA<br/>
     */
    /**
     * 
     * @param dep
     * @param maxDep
     * @param buf
     * @param res
     * @param flagArr
     */
    private static void dfs(int dep, int maxDep, char[] buf, char[] res,
            boolean[] flagArr) {
        if (dep == maxDep) {
            System.out.println(new String(res));
            return;
        }
        for (int i = 0; i < maxDep; i++) {
            if (!flagArr[i]
                    && (i != 0 && buf[i] == buf[i - 1] && flagArr[i - 1])) {
                // 當有重複的時候
                continue;
            }
            flagArr[i] = false;
            res[dep] = buf[i];
            dfs(dep + 1, maxDep, buf, res, flagArr);
            flagArr[i] = true;
        }
    }
}