[Ader] BOJ(14503): 로봇청소기 - 문제풀이

src/아더/BOJ_14503_로봇청소기.java

@@ -0,0 +1,92 @@
+package 아더;
+
+import java.io.*;
+
+public class BOJ_14503_로봇청소기 {
+    static int N, M, ANSWER;
+    static int[][] adj, dir = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
+    static boolean[][] visited;
+    static RobotCleaner rc;
+
+    static class RobotCleaner {
+        int r, c, d;
+
+        public RobotCleaner(int r, int c, int d) {
+            this.r = r;
+            this.c = c;
+            this.d = d;
+        }
+    }
+
+    public static void main(String[] args) {
+        try {
+            input();
+            solve();
+            print();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static void print() {
+        System.out.println(ANSWER);
+    }
+
+    private static void solve() {
+        dfs(rc.r, rc.c, rc.d);
+    }
+
+    private static void dfs(int r, int c, int d) {
+        if (adj[r][c] == 1) { // 벽 판단 -> 개선할 수 있는지 확인하기
+            return ;
+        } else if (!visited[r][c]){ // 방문체크 및 청소구역 갱신
+            visited[r][c] = true;
+            ANSWER++;
+        }
+
+        // 4방향 탐색
+        for (int k = 0; k < 4; k++) {
+            d = (d + 3) % 4; // 현재 방향에서 왼쪽으로 방향 전환
+            int nr = r + dir[d][0];
+            int nc = c + dir[d][1];
+
+            // 범위판단
+            if (nr < 0 || nc < 0 || nr >= N || nc >= M) continue;
+            // 벽판단
+            if (adj[nr][nc] == 1) continue;
+            // 방문판단
+            if (visited[nr][nc]) continue;
+
+            // dfs 수행
+            dfs(nr, nc, d);
+            return ;
+        }
+        // 4방향을 완료했으므로 뒤로 후진
+        dfs(r - dir[d][0], c - dir[d][1], d);
+        return ;
+    }
+
+    private static void input() throws IOException {
+        //BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedReader br = new BufferedReader(new FileReader(new File("/Users/woo-jinpark/Desktop/Park/05_Test/input/input.txt")));
+
+        String[] split = br.readLine().split(" ");
+        N = Integer.parseInt(split[0]);
+        M = Integer.parseInt(split[1]);
+        ANSWER = 0;
+        adj = new int[N][M];
+        visited = new boolean[N][M];
+
+        split = br.readLine().split(" ");
+        rc = new RobotCleaner(Integer.parseInt(split[0]),
+                Integer.parseInt(split[1]),
+                Integer.parseInt(split[2]));
+
+        for (int i = 0; i < N; i++) {
+            split = br.readLine().split(" ");
+            for (int j = 0; j < M; j++) {
+                adj[i][j] = Integer.parseInt(split[j]);
+            }
+        }
+    }
+}