[20250725] BOJ / G5 / 보물섬 / 이강현

Author: lkhyun

lkhyun/202507/25 BOJ G5 보물섬.md

@@ -0,0 +1,63 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main{
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static int N,M;
+    static char[][] map;
+    static List<int[]> lands;
+    static int[] di = {0,0,-1,1};
+    static int[] dj = {-1,1,0,0};
+    static int ans = 0;
+    public static void main(String[] args) throws Exception {
+        st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+        map = new char[N][M];
+        lands = new LinkedList<>();
+
+        for (int i = 0; i < N; i++) {
+            String line = br.readLine();
+            for (int j = 0; j < M; j++) {
+                map[i][j] = line.charAt(j);
+                if(map[i][j] == 'L'){
+                    lands.add(new int[]{i,j});
+                }
+            }
+        }
+        
+
+        for (int[] cur : lands) {
+            BFS(cur[0],cur[1]);
+        }
+        bw.write(ans+"");
+        bw.close();
+    }
+    static void BFS(int starti, int startj){
+        ArrayDeque<int[]> q = new ArrayDeque<>();
+        boolean[][] visited = new boolean[N][M];
+        q.add(new int[]{starti,startj,0});
+        visited[starti][startj] = true;
+
+        while(!q.isEmpty()){
+            int[] cur = q.poll();
+            ans = Math.max(ans,cur[2]);
+            
+            for (int k = 0; k < 4; k++) {
+                int ni = cur[0] + di[k];
+                int nj = cur[1] + dj[k];
+
+                if(ni<0 || ni>=N || nj<0 || nj>=M || visited[ni][nj]) continue;
+
+                if(map[ni][nj] == 'L'){
+                    q.add(new int[]{ni,nj,cur[2]+1});
+                    visited[ni][nj] = true;
+                }
+            }
+        }
+    }
+}
+```