Merge pull request #685 from AlgorithmWithGod/suyeun84

[20250818] BOJ / G4 / 치즈 / 김수연

Author: ShinHeeEul

suyeun84/202508/18 BOJ G4 치즈.md

@@ -0,0 +1,61 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class boj2636 {
+    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, time = 0, answer = 0;
+    static int[][] map;
+    static int[][] dir = new int[][]{{1,0}, {-1,0}, {0,1}, {0,-1}};
+    public static void main(String[] args) throws Exception {
+        nextLine();
+        N = nextInt();
+        M = nextInt();
+        map = new int[N][M];
+        for (int i = 0; i < N; i++) {
+            nextLine();
+            for (int j = 0; j < M; j++) {
+                map[i][j] = nextInt();
+                if (map[i][j] == 1) answer++;
+            }
+        }
+        while (answer > 0) {
+            time++;
+            int melted = solve();
+            if (answer - melted == 0) break;
+            answer -= melted;
+        }
+        System.out.println(time);
+        System.out.println(answer);
+    }
+    // 밖이랑 연결되어 있는지 확인
+    static int solve() {
+        Queue<int[]> q = new LinkedList<>();
+        boolean[][] visited = new boolean[N][M];
+        q.add(new int[]{0, 0});
+        int melted = 0;
+        visited[0][0] = true;
+        while(!q.isEmpty()) {
+            int[] cur = q.poll();
+            for (int[] d : dir) {
+                int ny = cur[0] + d[0];
+                int nx = cur[1] + d[1];
+                if (ny < 0 || ny >= N || nx < 0 || nx >= M || visited[ny][nx]) continue;
+                if (map[ny][nx] == 0) {
+                    visited[ny][nx] = true;
+                    q.add(new int[] {ny, nx});
+                } else {
+                    map[ny][nx] = 0;
+                    visited[ny][nx] = true;
+                    melted++;
+                }
+            }
+        }
+        return melted;
+    }
+}
+```