[BFS] baekjoon-7576

Author: Seogeurim

src/BFS/P7576/Main2.java

@@ -0,0 +1,61 @@
+package BFS.P7576;
+
+import java.io.*;
+import java.util.*;
+
+public class Main2 {
+
+    static int M, N, zero, cnt;
+    static int[][] map;
+    static int[] di = {-1, 0, 1, 0}, dj = {0, 1, 0, -1};
+    static Queue<Pos> q = new LinkedList<>();
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/BFS/P7576/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        M = Integer.parseInt(st.nextToken());
+        N = Integer.parseInt(st.nextToken());
+        map = new int[N][M];
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < M; j++) {
+                map[i][j] = Integer.parseInt(st.nextToken());
+                if (map[i][j] == 1) q.offer(new Pos(i, j, 0));
+                else if (map[i][j] == 0) zero ++;
+            }
+        }
+
+        while (!q.isEmpty()) {
+            Pos p = q.poll();
+            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) && map[to_i][to_j] == 0) {
+                    map[to_i][to_j] = 1;
+                    q.offer(new Pos(to_i, to_j, p.d+1));
+                    zero --;
+                }
+            }
+            cnt = p.d;
+        }
+
+        if (zero > 0) System.out.println(-1);
+        else System.out.println(cnt);
+    }
+
+    static boolean isValidPath(int i, int j) {
+        return 0 <= i && i < N && 0 <= j && j < M;
+    }
+
+    static class Pos {
+        int i, j, d;
+
+        public Pos(int i, int j, int d) {
+            this.i = i;
+            this.j = j;
+            this.d = d;
+        }
+    }
+}

src/BFS/P7576/README.md

@@ -2,3 +2,9 @@
 
 ![image](https://user-images.githubusercontent.com/22045163/96839353-052ce900-1484-11eb-845f-d76c0d11a9a3.png)
 
+![image](https://user-images.githubusercontent.com/22045163/114639163-21f5fb00-9d08-11eb-8a09-a236fd327ad9.png)
+
+### 2021.04.14
+
+- [210414.java](Main2.java)
+    ![image](https://user-images.githubusercontent.com/22045163/114639207-30441700-9d08-11eb-8c48-3f8ea4595757.png)