From cbd2671fc37a0b745561b0dedadba08fbd78fa57 Mon Sep 17 00:00:00 2001
From: Donew <47556347+03do-new30@users.noreply.github.com>
Date: Wed, 12 Feb 2025 22:14:51 +0900
Subject: [PATCH] =?UTF-8?q?[20250212]=20BOJ=20/=20G2=20/=20=EB=B6=88?=
 =?UTF-8?q?=EC=BC=9C=EA=B8=B0=20/=20=EC=8B=A0=EB=8F=99=EC=9C=A4?=
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---
 ...2 \353\266\210\354\274\234\352\270\260.md" | 103 ++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 "03do-new30/202502/12 BOJ G2 \353\266\210\354\274\234\352\270\260.md"

diff --git "a/03do-new30/202502/12 BOJ G2 \353\266\210\354\274\234\352\270\260.md" "b/03do-new30/202502/12 BOJ G2 \353\266\210\354\274\234\352\270\260.md"
new file mode 100644
index 00000000..4f2d8fe4
--- /dev/null
+++ "b/03do-new30/202502/12 BOJ G2 \353\266\210\354\274\234\352\270\260.md"	
@@ -0,0 +1,103 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public Main {
+    static class Point {
+        int r;
+        int c;
+        public Point(int r, int c) {
+            this.r = r;
+            this.c = c;
+        }
+    }
+
+    static int[] dr = {0, 0, -1, 1};
+    static int[] dc = {-1, 1, 0, 0};
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int N = Integer.parseInt(st.nextToken());
+        int M = Integer.parseInt(st.nextToken());
+
+        // 스위치 정보 저장
+        List<Point>[][] buttons = new ArrayList[N+1][N+1];
+        for (int i = 1; i < N+1; i++) {
+            for (int j = 1; j < N+1; j++) {
+                buttons[i][j] = new ArrayList<>();
+            }
+        }
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int r = Integer.parseInt(st.nextToken());
+            int c = Integer.parseInt(st.nextToken());
+            int nr = Integer.parseInt(st.nextToken());
+            int nc = Integer.parseInt(st.nextToken());
+            buttons[r][c].add(new Point(nr, nc));
+        }
+
+        // light[i][j] = (i, j) 방에 불이 켜짐
+        boolean[][] light = new boolean[N+1][N+1];
+        light[1][1] = true;
+        // visited[i][j] = (i, j)방에 도착함
+        boolean[][] visited = new boolean[N+1][N+1];
+        visited[1][1] = true;
+
+        Queue<Point> q = new ArrayDeque<>();
+        q.offer(new Point(1, 1));
+
+        // (i, j)로 움직일 수 있는 조건은
+        // light[i][j]가 참이면서 visited[i][j]가 참인 지점!
+        while (!q.isEmpty()) {
+            Point p = q.poll();
+
+            // p 지점에서 켤 수 있는 스위치를 모두 켠다
+            for (Point np : buttons[p.r][p.c]) {
+
+                if (light[np.r][np.c]) { continue; }
+
+                light[np.r][np.c] = true; // 스위치 켬
+
+                // 이전에 방문한 적이 있는데 이번에 불이 켜졌다면 도달 가능한 지점!
+                if (visited[np.r][np.c]) {
+                    q.offer(np); // 큐에 삽입
+                }
+            }
+
+            for (int i = 0; i < 4; i++) {
+
+                int nr = p.r + dr[i];
+                int nc = p.c + dc[i];
+
+                if (1 <= nr && nr < N+1 && 1 <= nc && nc < N+1) {
+                    if (visited[nr][nc]) { continue; }
+
+                    // 방문 표시
+                    visited[nr][nc] = true;
+                    // 만약 불이 켜져 있는 곳이라면 큐에 삽입!
+                    if (light[nr][nc]) {
+                        q.offer(new Point(nr, nc));
+                    }
+                }
+            }
+        }
+
+        int answer = 0;
+        for (int i = 1; i < N+1; i++) {
+            for (int j = 1; j < N+1; j++) {
+                if (light[i][j]) { answer++; }
+            }
+        }
+
+        bw.write(answer + "\n");
+
+
+        br.close();
+        bw.flush();
+        bw.close();
+    }
+}
+```