10026_적록색약 (JAVA)

10026번: 적록색약

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

public class Main {
	static class XY{
		int x; int y;
		public XY(int x, int y){
			this.x = x; this.y = y;
		}
	}

	static int N;
	static int[] dx = {-1,1,0,0};
	static int[] dy = {0,0,-1,1};
	static boolean[][] visited;
	static char[][] map;
	static int ans = 0;

	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		N = Integer.parseInt(br.readLine());
		visited = new boolean[N][N];
		map = new char[N][N];

		for(int i=0; i<N; i++){
			String str = br.readLine();
			for(int j=0; j<N; j++){
				map[i][j] = str.charAt(j);
			}
		}

		pre_bfs();
		System.out.println(ans);

		//초기화
		ans = 0;
		visited = new boolean[N][N]; //초기화
		for(int i=0; i<N; i++){
			for(int j=0; j<N; j++){
				if(map[i][j] == 'R')
					map[i][j] = 'G';
			}
		}

		pre_bfs();
		System.out.println(ans);

	}

	private static void pre_bfs(){
		for(int i=0; i<N; i++){
			for(int j=0; j<N; j++){
				if(!visited[i][j]){
					bfs(i,j);
					ans++;
				}
			}
		}
	}

	private static void bfs(int a, int b){
		Queue<XY> q = new LinkedList<>();
		q.offer(new XY(a,b));
		visited[a][b] = true;

		while(!q.isEmpty()){
			int x = q.peek().x;
			int y = q.peek().y;
			q.poll();

			for(int i=0; i<4; i++){
				int xx = x + dx[i];
				int yy = y + dy[i];

				if(xx>=0&&xx<N && yy>=0&&yy<N){
					if(map[x][y]==map[xx][yy] && !visited[xx][yy])
						bfs(xx, yy);
				}
			}
		}
	}
}

 

BFS탐색 - 초기화, R->G로 변경 - BFS탐색 순이다.