leetcode-go/poj/3278.catch-that-cow/Main.java

import java.io.*;
import java.util.*;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
    String s;
    int N, K;
    boolean[] set = new boolean[200001];
    Queue<Integer> queue = new LinkedList<Integer>();
    while ((s = in.readLine()) != null) {
      String[] nk = s.split("\\s+");
      N = Integer.parseInt(nk[0]);
      K = Integer.parseInt(nk[1]);
      Arrays.fill(set, 0, Math.max(N + 1, 2 * K + 1),false);
      queue.clear();
      queue.offer(N);
      set[N] = true;
      int cnt = 1, min = 0;
      while (cnt != 0) {
        int n = queue.poll();
        cnt--;
        if (n == K) break;
        if (n < K) {
          if (!set[2 * n]) {
            queue.offer(2 * n);
            set[2 * n] = true;
          }
          if (!set[n + 1]) {
            queue.offer(n + 1);
            set[n + 1] = true;
          }
        }
        if (0 < n && !set[n - 1]) {
          queue.offer(n - 1);
          set[n - 1] = true;
        }
        if (cnt == 0) {
          cnt = queue.size();
          min++;
        }
      }
      out.println(min);
      out.flush();
    }
  }
}