BOJ_17086 : 아기 상어 2

Author: spring0913

week3/BOJ_17086(아기 상어 2).java

@@ -0,0 +1,65 @@
+package week3;
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static int N, M;
+    public static int[][] shark;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        String[] input = br.readLine().split(" ");
+        N = Integer.parseInt(input[0]);
+        M = Integer.parseInt(input[1]);
+        shark = new int[N][M];
+        for(int i=0; i<N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for(int j=0; j<M; j++) {
+                shark[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+        int max = Integer.MIN_VALUE;
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<M; j++) {
+                if(shark[i][j] == 0) {
+                    max = Math.max(max, getSafeDistance(i, j));
+                }
+            }
+        }
+        System.out.println(max);
+    }
+
+    public static int getSafeDistance(int h, int w) {
+        int[] dh = {-1, -1, -1, 0, 0, 1, 1, 1};
+        int[] dw = {-1, 0, 1, -1, 1, -1, 0, 1};
+
+        int[][] visited = new int[N][M];
+        int min = Integer.MAX_VALUE;
+        Queue<int[]> q = new LinkedList<>();
+        q.offer(new int[]{h, w});
+        visited[h][w] = 1;
+        while(!q.isEmpty()) {
+            h = q.peek()[0];
+            w = q.peek()[1];
+            q.poll();
+
+            for(int i=0; i<8; i++) {
+                int nextH = h + dh[i];
+                int nextW = w + dw[i];
+                if(nextH >=0 && nextH < N && nextW >=0 && nextW < M) {
+                    if(visited[nextH][nextW] == 0) {
+                        if(shark[nextH][nextW] == 0) {
+                            visited[nextH][nextW] = visited[h][w] + 1;
+                            q.offer(new int[]{nextH, nextW});
+                        }else {
+                            min = Math.min(min, visited[h][w]);
+                        }
+                    }
+                }
+            }
+        }
+        return min;
+    }
+}