(코테) 백준_1697_숨박꼭질 BFS

 

package codingTest;

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

public class Backjun_1697_숨박꼭질 {

	static int N,M;  //N은 수빈 위치 M은 동생위치
	static boolean[] visted = new boolean[100001];
	 
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		N=Integer.parseInt(st.nextToken());
		M=Integer.parseInt(st.nextToken());		
		bfs(N);		
	}

	public static void bfs(int now) {
		 Queue<int[]> q = new LinkedList<>();
		 visted[now] = true;
		 q.offer(new int[] {now,0});
		while(!q.isEmpty()) {
			int[] qList=q.poll();
			int nowIndex = qList[0]; //현재 위치
			int nowDeep = qList[1]; //현재 이동횟수
			
			if(nowIndex==M) {  // 종료
				System.out.print(nowDeep);
				return;	
			}; 
			
			if(nowIndex*2 >= 0 && nowIndex*2 <= 100000 && !visted[nowIndex*2]) {
				visted[nowIndex*2] = true;
				q.offer(new int[] {nowIndex*2 , nowDeep+1});
			} 
				
			if(nowIndex+1 >= 0 && nowIndex+1 <= 100000 && !visted[nowIndex+1]) {
				visted[nowIndex+1] = true;
				q.offer(new int[] {nowIndex+1 , nowDeep+1});
			}
				
			if(nowIndex-1 >= 0 && nowIndex-1 <= 100000 && !visted[nowIndex-1]) {
				visted[nowIndex-1] = true;
				q.offer(new int[] {nowIndex-1 , nowDeep+1});
			} 
			
			/*
			//for문으로 위 if 문 3개 반복되는거 줄일 수 있음. 
			for (int next : new int[]{nowIndex - 1, nowIndex + 1, nowIndex * 2}) {
			    if (next >= 0 && next <= 100000 && !visited[next]) {
			        visited[next] = true;
			        q.offer(new int[]{next, nowDeep + 1});
			    }
			}



			 */
							
			
		}
	}
}