백준 1697

package baekjoon.DFS와BFS;

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

class Main1697 {

   static int N, K;
   static int[] dx = {-1, 1, 2};
   static int[] cnt;
   static boolean[] visited;

   public static void main(String[] args) throws Exception {
      input();
      bfs();
      System.out.println(cnt[K]);
   }

   private static void bfs() {
      Queue<Integer> q = new LinkedList<>();
      q.add(N);
      cnt[N] = 0;
      visited[N] = true;

      while (!q.isEmpty()) {
         int x = q.poll();
         for (int i = 0; i < 3; i++) {
            int nx = x + dx[i];
            if (i == 2)
               nx = x * dx[i];
            if (nx < 0 || nx > 100_000 || visited[nx])
               continue;
            cnt[nx] = cnt[x] + 1;
            visited[nx] = true;
            q.add(nx);
         }
      }
   }

   private static void input() throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      N = Integer.parseInt(st.nextToken());
      K = Integer.parseInt(st.nextToken());
      cnt = new int[100_005];
      visited = new boolean[100_005];
   }

}