백준: 14503번: 로봇 청소기

import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.InputStreamReader;

import java.util.StringTokenizer;

public class Main {

private static boolean Debug = false;

private static int MapSize_Y;

private static int MapSize_X;

private static int[][] Map;

private static int[][] Visited;

public static void main(String[] args) throws Exception {

BufferedReader br;

if (Debug && false) {

File f = new File("C:\\Users\\wvimi\\Downloads", "sample_input (11).txt");

FileReader reader = new FileReader(f);

br = new BufferedReader(reader);

} else {

br = new BufferedReader(new InputStreamReader(System.in)); // 직접입력시 이용

}

StringTokenizer st;

// 맵의 크기를 받는다.

st = new StringTokenizer(br.readLine());

MapSize_Y = Integer.parseInt(st.nextToken());

MapSize_X = Integer.parseInt(st.nextToken());

// 로봇의 위치를 받는다.

st = new StringTokenizer(br.readLine());

int startY = Integer.parseInt(st.nextToken());

int startX = Integer.parseInt(st.nextToken());

int rIndex = Integer.parseInt(st.nextToken());

// 맵 입력

Map = new int[MapSize_Y][];

Visited = new int[MapSize_Y][];

for (int i = 0; i < MapSize_Y; i++) {

st = new StringTokenizer(br.readLine());

Map[i] = new int[MapSize_X];

Visited[i] = new int[MapSize_X];

for (int j = 0; j < MapSize_X; j++) {

Map[i][j] = Integer.parseInt(st.nextToken());

}

}

moveRobot(startY, startX, rIndex);

int count = 0;

for (int i = 0; i < MapSize_Y; i++) {

for (int j = 0; j < MapSize_X; j++) {

if (Visited[i][j] == 1) {

count++;

}

}

}

System.out.println(count);

}

private static int[] rotY = { -1, 0, 1, 0 };

private static int[] rotX = { 0, 1, 0, -1 };

private static void moveRobot(int y, int x, int rIndex) {

Visited[y][x] = 1;

log("(%d,%d) 방문", y, x);

if (!isLeftClear(y, x, rIndex)) {

// Command 1

int nIndex = rIndex == 0 ? 3 : rIndex - 1;

int moveY = y + rotY[nIndex];

int moveX = x + rotX[nIndex];

moveRobot(moveY, moveX, nIndex);

} else if (!isAllClear(y, x)) {

// Command 2

int nIndex = rIndex == 0 ? 3 : rIndex - 1;

moveRobot(y, x, nIndex); // 방향 전환

} else if (isMoveBack(y, x, rIndex)) {

// Command 3

int nIndex = rIndex < 2 ? rIndex + 2 : rIndex - 2;

int moveY = y + rotY[nIndex];

int moveX = x + rotX[nIndex];

moveRobot(moveY, moveX, rIndex); // 방향은 유지한 채로 뒤로 한 발자국

} else {

// Command 4

log("I've Done");

}

}

// 로봇의 왼쪽 방향이 깨끗한지

private static boolean isLeftClear(int y, int x, int rIndex) {

int sIndex = rIndex == 0 ? 3 : rIndex - 1;

int moveY = y + rotY[sIndex];

int moveX = x + rotX[sIndex];

if (moveY < 0 || moveY >= MapSize_Y || moveX < 0 || moveX >= MapSize_X) {

return true;

} else if (Map[moveY][moveX] == 1) {

return true;

} else if (Visited[moveY][moveX] == 1) {

return true;

}

return false;

}

// 모든 방향 모두 깨끗한지

private static boolean isAllClear(int y, int x) {

for (int i = 0; i < 4; i++) {

if (!isLeftClear(y, x, i)) {

return false;

}

}

return true;

}

// 후진이 가능한지

private static boolean isMoveBack(int y, int x, int rIndex) {

int sIndex = rIndex < 2 ? rIndex - 2 + 4 : rIndex - 2;

int moveY = y + rotY[sIndex];

int moveX = x + rotX[sIndex];

if (moveY < 0 || moveY >= MapSize_Y || moveX < 0 || moveX >= MapSize_X) {

return false;

} else if (Map[moveY][moveX] == 1) {

return false;

}

return true;

}

public static void log(String input) {

if(Debug) {

System.out.println(input);

}

}

public static void log(String input, Object... args) {

if(Debug) {

System.out.println(String.format(input, args));

}

}

}