[백준] 2931* 가스관 (골드2)

https://www.acmicpc.net/problem/2931

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

public class Main {
    static int r, c, startX, startY, startDir, ansX = -1, ansY = -1, totalPipe;
    static char[][] map;
    static boolean[][] visited;
    static int[] dx = {-1, 0, 1, 0}, dy = {0, 1, 0, -1};
    static char[] pipe = {'1', '2', '3', '4', '-', '|', '+'};

    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        r = Integer.parseInt(st.nextToken());
        c = Integer.parseInt(st.nextToken());
        map = new char[r][c];

        for (int i = 0; i < r; i++) {
            map[i] = br.readLine().toCharArray();
            for (int j = 0; j < c; j++) {
                if (map[i][j] == 'M') {
                    startY = i; startX = j;
                }
                if (map[i][j] != '.') totalPipe++;
            }
        }
        totalPipe++;
        // 시작 방향 찾기
        for (int i = 0; i < 4; i++) {
            int nx = startX + dx[i], ny = startY + dy[i];
            if (isValid(nx, ny) && map[ny][nx] != '.' && map[ny][nx] != 'Z') {
                startDir = i;
            }
        }
        simulate(startX, startY, startDir);
        for (char p : pipe) {
            map[ansY][ansX] = p;
            if (simulate(startX, startY, startDir) == totalPipe) {
                System.out.println((ansY + 1) + " " + (ansX + 1) + " " + p);
                return;
            }
        }
    }

    static boolean isValid(int x, int y) {
        return y >= 0 && y < r && x >= 0 && x < c;
    }

    static int simulate(int x, int y, int dir) {
        visited = new boolean[r][c];
        visited[y][x] = true;
        int count = 1;

        while (true) {
            x += dx[dir];
            y += dy[dir];
            if (!isValid(x, y) || !canEnter(x, y, dir)) break;
            char cell = map[y][x];
            if (cell == '.') {
                if (ansX == -1) { ansX = x; ansY = y; }
                break;
            }
            if (cell == 'Z') return count + 1;
            if (!visited[y][x]) {
                visited[y][x] = true;
                count++;
            }
            dir = getNewDir(x, y, dir);
        }
        return count;
    }

    static boolean canEnter(int x, int y, int dir) {
        char c = map[y][x];
        if (c == '.' || c == 'Z' || c == '+') return true;
        if (c == '-') return dir == 0 || dir == 2;
        if (c == '|') return dir == 1 || dir == 3;
        if (c == '1') return dir == 0 || dir == 3;
        if (c == '2') return dir == 0 || dir == 1;
        if (c == '3') return dir == 1 || dir == 2;
        if (c == '4') return dir == 2 || dir == 3;
        return false;
    }

    static int getNewDir(int x, int y, int dir) {
        char c = map[y][x];
        if (c == '-' || c == '|' || c == '+') return dir;
        if (c == '1') return dir == 0 ? 1 : 2;
        if (c == '2') return dir == 0 ? 3 : 2;
        if (c == '3') return dir == 1 ? 0 : 3;
        if (c == '4') return dir == 2 ? 1 : 0;
        return dir;
    }
}

시뮬레이션 아닌 버전

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main {
	static int 			R;
	static int 			C;
	static int[][]		map;
	static char[][]		realMap;
	static int[]		dx = {0, 1, 0, -1};
	static int[]		dy = {1, 0, -1, 0};
	static int[]		convert = new int[128];
	static char[]		reverseConvert = {0, 0, 0, '1', 0, '|', '2', 0, 0, '4', '-', 0, '3', 0, 0, '+'};
	static int			ansX;
	static int			ansY;
	static int			ansDir;
	
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		StringBuilder sb = new StringBuilder();
		StringTokenizer st;
		
		init();
		st = new StringTokenizer(br.readLine());
		R = Integer.parseInt(st.nextToken());
		C = Integer.parseInt(st.nextToken());
		map = new int[R][C];
		realMap = new char[R][];
		ansDir = 0;
		for (int y = 0; y < R; y++) {
			realMap[y] = br.readLine().toCharArray();
			for (int x = 0; x < C; x++) {
				map[y][x] = convert[realMap[y][x]];
			}
		}
		simulation();
		sb.append(ansY).append(' ').append(ansX).append(' ').append(reverseConvert[ansDir]).append('\n');
		bw.write(sb.toString());
		bw.flush();
		bw.close();
	}
	
	private static void simulation() {
		for (int y = 0; y < R; y++) {
			for (int x = 0; x < C; x++) {
				if (realMap[y][x] != '.')
					continue;
				ansX = x + 1;
				ansY = y + 1;
				for (int i = 0; i < 4; i++) {
					int nx = x + dx[i];
					int ny = y + dy[i];
					if (nx < 0 || nx >= C || ny < 0 || ny >= R)
						continue;
					if ((map[ny][nx] & (1 << (i + 2) % 4)) != 0 && realMap[ny][nx] != 'Z' && realMap[ny][nx] != 'M') {
						ansDir = ansDir | (1 << i);
					}
				}
				if (ansDir != 0)
					return ;
			}
		}
	}

	private static void init() {
		convert['1'] = 3;
		convert['2'] = 6;
		convert['3'] = 12;
		convert['4'] = 9;
		convert['-'] = 10;
		convert['|'] = 5;
		convert['+'] = 15;
		convert['M'] = 15;
		convert['Z'] = 15;
	}
}