poj 1750 java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static StringBuffer[]b=new StringBuffer[11];
    public static int blank;
    public static void main(String[]args) throws IOException{
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String str="" ;
        String next;
        blank=0;
        init();
        while((next = in.readLine())!=null){
            Write(str,next);    
            str = next;
        }
    }
    public static void Write(String str,String next){
        int same = gsn(str,next);
        if(same>blank){
            blank++;
        }else if(same<blank){
            blank=same;
        }
        System.out.println(b[blank]+next);    
    }
    public static int gsn(String s1,String s2){//getSameNumber
        int len = s1.length()>s2.length()?s2.length():s1.length();
        int i;
        for(i=0;i<len;i++){
            if(s1.charAt(i)!=s2.charAt(i)){
                break;
            }
        }
        return i;
    }
    
    public static void init(){
        StringBuffer sb ;
        for(int i=0;i<11;i++){
            sb = new StringBuffer("");
            for(int j=0;j<i;j++){
                sb.append(" ");
            }
            b[i]=sb;
        }
    }
}