[20250729] BOJ / G5 / 방탈출 / 김수연

suyeun84/202507/29 BOJ G5 방탈출.md

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+```java
+import java.util.*;
+import java.io.*;
+
+public class boj23352 {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static StringTokenizer st;
+    static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+    static int nextInt() {return Integer.parseInt(st.nextToken());}
+
+    static int N, M, answer, dep;
+    static int[][] map;
+    static int[][] dir = {{1,0}, {0,1}, {0,-1}, {-1,0}};
+    public static void main(String[] args) throws Exception {
+        nextLine();
+        N = nextInt();
+        M = nextInt();
+        map = new int[N][M];
+        answer = 0;
+        dep = 0;
+        for (int i = 0; i < N; i++) {
+            nextLine();
+            for (int j = 0; j < M; j++) map[i][j] = nextInt();
+        }
+        for (int i = 0; i < N; i++) {
+            for (int j = 0; j < M; j++) {
+                if (map[i][j] == 0) continue;
+                bfs(i, j);
+            }
+        }
+        System.out.println(answer);
+    }
+
+    static void bfs(int y, int x) {
+        boolean[][] visited = new boolean[N][M];
+        Queue<Pos> q = new LinkedList<>();
+        q.add(new Pos(y, x, 0));
+        visited[y][x] = true;
+
+        while (!q.isEmpty()) {
+            Pos curr = q.poll();
+            boolean flag = true;
+
+            for (int[] d : dir) {
+                int ny = curr.y + d[0];
+                int nx = curr.x + d[1];
+                if (ny < 0 || ny >= N || nx < 0 || nx >= M || visited[ny][nx] || map[ny][nx] == 0) continue;
+                visited[ny][nx] = true;
+                flag = false;
+                q.add(new Pos(ny, nx, curr.cnt+1));
+            }
+            if (flag) {
+                if (dep < curr.cnt) {
+                    dep = curr.cnt;
+                    answer = map[y][x] + map[curr.y][curr.x];
+                } else if (dep == curr.cnt) {
+                    answer = Math.max(answer, map[y][x] + map[curr.y][curr.x]);
+                }
+            }
+        }
+    }
+}
+
+class Pos {
+    int y, x, cnt;
+    public Pos(int y, int x, int cnt) {
+        this.y = y;
+        this.x = x;
+        this.cnt = cnt;
+    }
+}
+```