[DFS] baekjoon-4963

Author: Seogeurim

Diff for: README.md

@@ -27,6 +27,7 @@
 | 08  |     | [Baekjoon-10971 외판원 순회 2](./src/DFS/P10971) |      |
 | 09  |     | [Baekjoon-14500 테트로미노](./src/DFS/P14500) |      |
 | 10  |     | [Baekjoon-2667 단지번호붙이기](./src/DFS/P2667) |      |
+| 11  |     | [Baekjoon-4963 섬의 개수](./src/DFS/P4963) |      |
 
 ### BFS
 

Diff for: src/DFS/P4963/Main.java

@@ -0,0 +1,77 @@
+package DFS.P4963;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+public class Main {
+
+    static int w, h;
+    static int[][] map;
+    static boolean[][] visited;
+
+    static int[] di = {-1, 0, 1, 0, -1, 1, 1, -1};
+    static int[] dj = {0, 1, 0, -1, 1, 1, -1, -1};
+
+    static int count;
+    static boolean flag = false;
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/DFS/P4963/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        while (true) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            w = Integer.parseInt(st.nextToken());
+            h = Integer.parseInt(st.nextToken());
+            if (w == 0 && h == 0) return;
+
+            map = new int[h][w];
+            visited = new boolean[h][w];
+            count = 0;
+
+            for (int i = 0; i < h; i++) {
+                st = new StringTokenizer(br.readLine());
+                for (int j = 0; j < w; j++) {
+                    map[i][j] = Integer.parseInt(st.nextToken());
+                }
+            }
+
+            for (int i = 0; i < h; i++) {
+                for (int j = 0; j < w; j++) {
+                    if (!visited[i][j]) {
+                        dfs(i, j);
+                        if (flag) {
+                            count ++;
+                            flag = false;
+                        }
+                    }
+                }
+            }
+
+            System.out.println(count);
+        }
+    }
+
+    static void dfs(int cur_i, int cur_j) {
+        visited[cur_i][cur_j] = true;
+
+        if (map[cur_i][cur_j] == 1) {
+            flag = true;
+
+            for (int t = 0; t < 8; t++) {
+                int to_i = cur_i + di[t];
+                int to_j = cur_j + dj[t];
+
+                if (isValidPath(to_i, to_j) && !visited[to_i][to_j]) {
+                    dfs(to_i, to_j);
+                }
+            }
+        }
+    }
+
+    static boolean isValidPath(int i, int j) {
+        return 0 <= i && i < h && 0 <= j && j < w;
+    }
+}

Diff for: src/DFS/P4963/README.md

@@ -0,0 +1,3 @@
+## [baekjoon-4963] 섬의 개수
+
+![image](https://user-images.githubusercontent.com/22045163/96835296-5cc85600-147e-11eb-9061-ff95a69e7a34.png)

Diff for: src/DFS/P4963/input.txt

@@ -0,0 +1,25 @@
+1 1
+0
+2 2
+0 1
+1 0
+3 2
+1 1 1
+1 1 1
+5 4
+1 0 1 0 0
+1 0 0 0 0
+1 0 1 0 1
+1 0 0 1 0
+5 4
+1 1 1 0 1
+1 0 1 0 1
+1 0 1 0 1
+1 0 1 1 1
+5 5
+1 0 1 0 1
+0 0 0 0 0
+1 0 1 0 1
+0 0 0 0 0
+1 0 1 0 1
+0 0