BOJ_14502 : 연구소

Author: spring0913

week11/BOJ_14502(연구소).java

@@ -0,0 +1,100 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    private static int[][] virus;
+    private static int N, M;
+    private static List<int[]> space;
+    private static int answer = 0;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+        virus = new int[N][M];
+        space = new ArrayList<>();
+        for(int i=0; i<N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for(int j=0; j<M; j++) {
+                virus[i][j] = Integer.parseInt(st.nextToken());
+                if(virus[i][j] == 0) {
+                    space.add(new int[]{i, j});
+                }
+            }
+        }
+        dfs(0, 0, new ArrayList<>());
+        System.out.println(answer);
+    }
+
+    public static void dfs(int start, int index, List<int[]> wall) {
+        if(index == 3) {
+            answer = Math.max(answer, bfs(copyArr(), wall));
+            return;
+        }
+
+        for(int i=start; i<space.size(); i++) {
+            int h = space.get(i)[0];
+            int w = space.get(i)[1];
+            wall.add(new int[]{h, w});
+            dfs(i+1, index+1, wall);
+            wall.remove(index);
+        }
+    }
+
+    public static int bfs(int[][] virus, List<int[]> wall) {
+        int[] dh = {0, 1, 0, -1};
+        int[] dw = {-1, 0, 1, 0};
+        Queue<int[]> q = new LinkedList<>();
+        boolean[][] visited = new boolean[N][M];
+        for(int i=0; i<3; i++) {
+            virus[wall.get(i)[0]][wall.get(i)[1]] = 1;
+        }
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<M; j++) {
+                if(virus[i][j] == 2) {
+                    q.offer(new int[]{i, j});
+                    visited[i][j] = true;
+                }
+            }
+        }
+        while(!q.isEmpty()) {
+            int h = q.peek()[0];
+            int w = q.peek()[1];
+            q.poll();
+            for(int i=0; i<4; i++) {
+                int nextH = h + dh[i];
+                int nextW = w + dw[i];
+                if(nextH >= 0 && nextH < N && nextW >= 0 && nextW < M) {
+                    if(!visited[nextH][nextW] && virus[nextH][nextW] == 0) {
+                        visited[nextH][nextW] = true;
+                        virus[nextH][nextW] = 2;
+                        q.offer(new int[]{nextH, nextW});
+                    }
+                }
+            }
+        }
+        return getSafeZone(virus);
+    }
+
+    public static int[][] copyArr() {
+        int[][] arr = new int[N][M];
+        for(int i=0; i<N; i++) {
+            arr[i] = virus[i].clone();
+        }
+        return arr;
+    }
+
+    public static int getSafeZone(int[][] virus) {
+        int count = 0;
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<M; j++) {
+                if(virus[i][j] == 0) {
+                    count++;
+                }
+            }
+        }
+        return count;
+    }
+}