백준 16953

package baekjoon.그리디;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class Main16953 {

   public static void main(String[] args) throws Exception {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      int A = Integer.parseInt(st.nextToken());
      int B = Integer.parseInt(st.nextToken());
      Queue<Pair> q = new LinkedList<>();

      q.add(new Pair(A, 1));
      while (!q.isEmpty()) {
         Pair tmp = q.poll();
         if (tmp.a == B) {
            System.out.println(tmp.c);
            return;
         }
         if (tmp.a > B) {
            continue;
         }
         if ((tmp.a * 2) <= B) {
            q.add(new Pair(tmp.a * 2, tmp.c + 1));
         }
         if ((tmp.a * 10) + 1 <= B) {
            q.add(new Pair((tmp.a * 10) + 1, tmp.c + 1));
         }
      }
      System.out.println(-1);
   }

   private static class Pair {
      long a;
      int c;


      public Pair(long a, int c) {
         this.a = a;
         this.c = c;
      }
   }

}