Poj Solution 2577

http://poj.org/problem?id=2577

//* @author  mekarlos@gmail.com
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
 public static void main(String[] args) throws IOException {
  BufferedReader stdin=new BufferedReader(new InputStreamReader(System.in));
  int[] ram=new int[1000];
  int[] reg=new int[10];
  int pos=0;
  int num=1;
  while(stdin.ready()){
   ram[pos++]=new Integer(stdin.readLine());
  }
  pos=0;
  while(ram[pos]!=100){
   switch(ram[pos]/100){
    case 0:
    if(reg[ram[pos]%10]==0){
        pos++;
    }
    else{
        pos=reg[(ram[pos]%100)/10];
    }
    break;
    case 2:
    reg[(ram[pos]%100)/10]=ram[pos]%10;
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 3:
    reg[(ram[pos]%100)/10]+=(ram[pos]%10);
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 4:
    reg[(ram[pos]%100)/10]*=(ram[pos]%10);
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 5:
    reg[(ram[pos]%100)/10]=reg[ram[pos]%10];
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 6:
    reg[(ram[pos]%100)/10]+=reg[ram[pos]%10];
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 7:
    reg[(ram[pos]%100)/10]*=reg[ram[pos]%10];
    reg[(ram[pos]%100)/10]%=1000;
    pos++;
    break;
    case 8:
    reg[(ram[pos]%100)/10]=ram[reg[ram[pos]%10]];
    pos++;
    break;
    case 9:
    ram[reg[ram[pos]%10]]=reg[(ram[pos]%100)/10];
    pos++;
    break;
   }
  num++;
 }
  System.out.println(num);        
 }
}