[20250712] BOJ / G5 / 토마토 / 이인희

LiiNi-coder/202507/12 BOJ 토마토.md

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+```java
+import java.awt.Point;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayDeque;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.StringTokenizer;
+
+public class B7576 {
+	private static BufferedReader br;
+	private static ArrayDeque<IntAndPoint> q;
+	private static StringTokenizer st;
+	private static HashSet<Point> wall_tomato_set;
+	private static int[][] drdcs = {
+			{1, 0},
+			{0, -1},
+			{-1, 0},
+			{0, 1}
+	};
+
+	private static class IntAndPoint{
+		Point p; int level;
+		public IntAndPoint(Point p, int level) {
+			this.p = p;
+			this.level = level;
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		br = new BufferedReader(new InputStreamReader(System.in));
+
+		//입력
+		int n, m;
+		String[] temp = br.readLine().split(" ");
+		m = Integer.parseInt(temp[0]);
+		n = Integer.parseInt(temp[1]);
+		q = new ArrayDeque<IntAndPoint>();
+		wall_tomato_set = new HashSet<Point>();
+		for(int r=0; r<n; r++) {
+			st = new StringTokenizer(br.readLine());
+			for(int c = 0; c<m; c++) {
+				int value = Integer.parseInt(st.nextToken());
+				if(value==1) {
+					q.add(new IntAndPoint(new Point(r, c), 0));
+				}else if(value == -1)
+					wall_tomato_set.add(new Point(r, c));
+			}
+		}
+
+		int max_level = 0;
+		// bfs 진행
+		while(!q.isEmpty()) {
+			var temp1 = q.pollFirst();
+			Point p = temp1.p;
+			wall_tomato_set.add(p);
+			int level = temp1.level;
+			max_level = Math.max(max_level, level);
+
+			for(int[] drdc : drdcs) {
+				Point next_p = new Point(p.x + drdc[0], p.y + drdc[1]);
+				//범위체크
+				if(next_p.x <0 || next_p.x >= n || next_p.y <0 || next_p.y >= m) {
+					continue;
+				}
+				// 벽인지와 토마토인지 확인
+				if(wall_tomato_set.contains(next_p))
+					continue;
+				q.addLast(new IntAndPoint(next_p, level+1));
+			}	
+		}
+
+		// 만약 벽 또는 토마토의 개수가 n*m개수와 다르면 불가능
+		if(wall_tomato_set.size() != n*m) {
+			System.out.println(-1);
+		}else {
+			System.out.println(max_level);
+		}
+		br.close();
+	}
+
+}
+```