Open Judge 4001 - Catch That Cow - BFS

import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;

/**
 * 
 * @author XA-GDD
 *
 */
public class Main{
	static int N,K;
	static int [] moveStep = {1,-1,0}; 
	static int _Max_K = 100000;
	static boolean [] visited = new boolean [100003];
	static int [] minCost = new int [100003];
	
	public static void main(String[] args) throws IOException {	
		Scanner reader=new Scanner(System.in);
		N=reader.nextInt();
		K=reader.nextInt();
		reader.close();
		if (N >= K) {
			System.out.println(N - K); //农夫比牛远时，只能往回走，即距离需要减少，而走的方式时，减少的只有-1
		}else {
			System.out.println(bfs(N,K));
		}
	
	}
	
	static int bfs(int start , int end) {
		int minStep = 0;
		PriorityQueue<int[]> pq = new PriorityQueue<int[]>(new Comparator<int[]>() {
			@Override
			public int compare(int[] o1, int[] o2) {
				return o1[1]-o2[1];
			}
		});
		Arrays.fill(visited,false);
		Arrays.fill(minCost,Integer.MAX_VALUE>>1);
		pq.add(new int[] {start,0});
		minCost[start] = 0;
		
		while(!pq.isEmpty()) {
			int curr[] = pq.poll();
			if(curr[0] == end ) {
				minStep = curr[1];
				break;
			}	
			if(visited[curr[0]]) {
				continue;
			}
			visited[curr[0]]=true;
			
			for(int i=0;i<moveStep.length;i++) {
				int nextNode = 0;
				if(moveStep[i]==0) {
					nextNode = curr[0]*2;
				}else {
					nextNode = curr[0]+moveStep[i];
				}
				if(nextNode<=_Max_K && nextNode>0) {
					if(minCost[curr[0]]+1<minCost[nextNode]) {
						minCost[nextNode]=minCost[curr[0]]+1;
						pq.add(new int[] {nextNode,minCost[nextNode]});
					}
				}
			}
		}
		
		return minStep;
	}
	

}