华为2014机试题，压缩字符

import java.util.Scanner;

public class StringFilter {

public static void main(String[]args){

Scanner sc=new Scanner(System.in);

String str=sc.nextLine();

char[] ch=str.toCharArray();

char[] rech=new char[ch.length];

rech[0]=ch[0];

int count=0;

for(int i=1;i<ch.length;i++){

boolean flag=true;

for(int j=0;j<=count;j++){

if(ch[i]==rech[j]){

flag=false;

}

}

if(flag){

count++;

rech[count]=ch[i];

}

}

for(int j=0;j<=count;j++){

System.out.print(rech[j]);

}

}

}