[Simulation] baekjoon-2636

Author: Seogeurim

README.md

@@ -52,6 +52,7 @@
 | 19  |     | [Baekjoon-2931 가스관](./src/Simulation/P2931)        |      |
 | 20  |     | [JUNGOL-1205 조커](./src/Simulation/jo1205)           |      |
 | 21  |     | [SWEA-1767 프로세서 연결하기](./src/Simulation/swea1767) |      |
+| 22  |     | [Baekjoon-2636 치즈](./src/Simulation/P2636)          |      |
 
 ## String
 

src/Simulation/P2636/Main.java

@@ -0,0 +1,83 @@
+package Simulation.P2636;
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int R, C, total;
+    static int[][] map;
+    static int[] di = {-1, 0, 1, 0};
+    static int[] dj = {0, 1, 0, -1};
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/Simulation/P2636/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        R = Integer.parseInt(st.nextToken());
+        C = Integer.parseInt(st.nextToken());
+
+        map = new int[R][C];
+        for (int i = 0; i < R; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < C; j++) {
+                map[i][j] = Integer.parseInt(st.nextToken());
+                if (map[i][j] == 1) total ++;
+            }
+        }
+
+        solve();
+    }
+
+    static void solve() {
+        Queue<Pos> air = new LinkedList<>();
+        Queue<Pos> cheese = new LinkedList<>();
+        boolean[][] visited = new boolean[R][C];
+        int time = 0;
+
+        air.add(new Pos(0, 0));
+        while (total > 0) {
+            time ++;
+
+            while (!air.isEmpty()) {
+                Pos p = air.poll();
+                visited[p.i][p.j] = true;
+
+                for (int k = 0; k < 4; k++) {
+                    int to_i = p.i + di[k];
+                    int to_j = p.j + dj[k];
+
+                    if (!isValidPath(to_i, to_j) || visited[to_i][to_j]) continue;
+
+                    visited[to_i][to_j] = true;
+                    if (map[to_i][to_j] == 0) {
+                        air.offer(new Pos(to_i, to_j));
+                    } else {
+                        cheese.offer(new Pos(to_i, to_j));
+                        total --;
+                    }
+                }
+            }
+
+            air.addAll(cheese);
+            cheese.clear();
+        }
+
+        System.out.println(time);
+        System.out.println(air.size());
+    }
+
+    static boolean isValidPath(int i, int j) {
+        return 0 <= i && i < R && 0 <= j && j < C;
+    }
+
+    static class Pos {
+        int i, j;
+
+        public Pos(int i, int j) {
+            this.i = i;
+            this.j = j;
+        }
+    }
+}

src/Simulation/P2636/README.md

@@ -0,0 +1,10 @@
+## [baekjoon-2636] 치즈
+
+![image](https://user-images.githubusercontent.com/22045163/112263513-c610f700-8cb2-11eb-8d80-01e84e3278fb.png)
+![image](https://user-images.githubusercontent.com/22045163/112263652-ff496700-8cb2-11eb-9452-7bbb8325a011.png)
+
+### 풀이 과정
+
+어떻게 풀이해야 할지 몰라 한참을 생각했다. 그 이유는 초점을 치즈에 맞추고 있었기 때문이다. 풀이법이 생각나지 않는다면 초점을 바꿔서 생각해보자. 이 문제는 `뭉치를 둘러싸고 있는 것들`에 관심이 있기 때문에, 치즈가 아닌 `공기`에 초점을 맞춰 문제를 풀어나가야 한다. 공기의 입장에서 BFS를 수행하면 쉽게 풀어나갈 수 있다.
+
+![image](https://user-images.githubusercontent.com/22045163/112263564-dcb74e00-8cb2-11eb-8b67-b125390f4bc0.png)

src/Simulation/P2636/input.txt

@@ -0,0 +1,14 @@
+13 12
+0 0 0 0 0 0 0 0 0 0 0 0
+0 0 0 0 0 0 0 0 0 0 0 0
+0 0 0 0 0 0 0 1 1 0 0 0
+0 1 1 1 0 0 0 1 1 0 0 0
+0 1 1 1 1 1 1 0 0 0 0 0
+0 1 1 1 1 1 0 1 1 0 0 0
+0 1 1 1 1 0 0 1 1 0 0 0
+0 0 1 1 0 0 0 1 1 0 0 0
+0 0 1 1 1 1 1 1 1 0 0 0
+0 0 1 1 1 1 1 1 1 0 0 0
+0 0 1 1 1 1 1 1 1 0 0 0
+0 0 1 1 1 1 1 1 1 0 0 0
+0 0 0 0 0 0 0 0 0 0 0 0