[유경민] 토마토

solution/BOJ_7576_토마토/ykm.java

@@ -0,0 +1,77 @@
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static int map[][];
+    static int row;
+    static int col;
+
+    static Queue<int[]> q = new LinkedList<int[]>();
+    static int[] dx = { -1, 1, 0, 0 };
+    static int[] dy = { 0, 0, -1, 1 };
+
+    static int area = 0; // 익혀야 되는 토마토의 개수
+
+    public static void main(String[] args) throws IOException {
+        System.setIn(new FileInputStream("input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        col = Integer.parseInt(st.nextToken());
+        row = Integer.parseInt(st.nextToken());
+        map = new int[row][col];
+
+
+        for (int i = 0; i < row; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < col; j++) {
+                map[i][j] = Integer.parseInt(st.nextToken());
+                if (map[i][j] == 1) {
+                    q.add(new int[] { i, j, 1 });
+                } else if (map[i][j] == 0) {
+                    area++;
+                }
+            }
+        }
+
+        if (area == 0) {
+            System.out.println(0);
+        } else {
+            int turn = spread();
+
+            if (area != 0)
+                System.out.println(-1);
+            else
+                System.out.println(turn);
+
+        }
+
+        br.close();
+
+    }
+
+    private static int spread() {
+        int turn = 0;
+
+        while (!q.isEmpty()) {
+            int[] current = q.poll();
+
+            for (int i = 0; i < 4; i++) {
+                int nextX = current[0] + dx[i];
+                int nextY = current[1] + dy[i];
+
+                if (nextX < 0 || nextY < 0 || nextX >= row || nextY >= col)
+                    continue;
+
+                if (map[nextX][nextY] == 0) {
+                    map[nextX][nextY] = current[2] + 1;
+                    turn = Math.max(turn, map[nextX][nextY]);
+                    q.add(new int[] { nextX, nextY, current[2] + 1 });
+                    area --;
+                }
+            }
+        }
+
+        return turn - 1 ;
+    }
+}