Poj Solution 3049

http://poj.org/problem?id=3049

//* @author: ccQ.SuperSupper
import java.io.*;
import java.util.*;

public class Main {
    
    static final int N = 20;
    static int n,l;
    static String ans;
    static char word[] = new char[N];
    static char ansp[] = new char[N];
    
    public static void main(String []args)throws Exception{
        
        int i;
        String str;
        //Scanner cin = new Scanner(new FileInputStream("input.txt"));
        Scanner cin = new Scanner(System.in);
        l = cin.nextInt();
        n = cin.nextInt();
        for(i=0;i< n;++i){
            str = cin.next();
            word[i] = str.charAt(0);
        }
        Arrays.sort(word,0,n);
        dfs(0,0,false);
    }

public static void dfs(int start,int dept,boolean have){
    int i;
    if(dept>=l){
        if(!have) return ;
        for(i=0;i< dept;++i)
            System.out.print(ansp[i]);
        System.out.println("");
        return ;
    }
    for(i=start;i< n;++i){
      ansp[dept] = word[i];
         if(word[i]=='a' || word[i]=='e'||word[i]=='i'||word[i]=='o'||word[i]=='u'){
        dfs(i+1,dept+1,have|true);
       }
        else dfs(i+1,dept+1,have);
    }
 }
}