[황정훈] 토마토

solution/BOJ_7576_토마토/황정훈.java

@@ -0,0 +1,83 @@
+import java.io.*;
+import java.util.*;
+
+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 boolean done = false;
+    static boolean[][] already;
+    static int N, M, D = -1;
+    static int[] dr = {-1, 0, 1, 0};
+    static int[] dc = {0, 1, 0, -1};
+    static int[][] arr;
+    static class Pos{
+        int r, c;
+        public Pos(int r, int c){
+            this.r = r;
+            this.c = c;
+        }
+    }
+    static ArrayList<Pos> pre, post;
+
+    public static void main(String[] args) throws IOException {
+
+        st = new StringTokenizer(br.readLine());
+        M = Integer.parseInt(st.nextToken());
+        N = Integer.parseInt(st.nextToken());
+
+        arr = new int[N][M];
+        already = new boolean[N][M];
+        pre = new ArrayList<>();
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < M; j++) {
+                arr[i][j] = Integer.parseInt(st.nextToken());
+                if (arr[i][j] == 1) pre.add(new Pos(i, j));
+            }
+        }
+
+        while(!done){
+            check();
+            flow();
+            if(pre.isEmpty() && !done){
+                D = -1;
+                break;
+            }
+            D++;
+        }
+        bw.write(D+"\n");
+
+        br.close();
+        bw.flush();
+        bw.close();
+    }
+    static void check(){
+        for (int i = 0; i < N; i++) {
+            for (int j = 0; j < M; j++) {
+                if (arr[i][j] == 0) return;
+            }
+        }
+        done = true;
+    }
+    static void flow(){
+        post = new ArrayList<>();
+        for(Pos point : pre){
+            int r = point.r;
+            int c = point.c;
+            already[r][c] = true;
+            for (int w = 0; w < 4; w++) {
+                int nr = r + dr[w];
+                int nc = c + dc[w];
+                if (0<=nr && nr<N && 0<=nc && nc<M && arr[nr][nc]==0 && !already[nr][nc]){
+                    arr[nr][nc] = 1;
+                    post.add(new Pos(nr, nc));
+                    already[nr][nc] = true;
+                }
+            }
+        }
+        pre = post;
+    }
+}