[DFS] baekjoon-1987

Author: Seogeurim

README.md

@@ -90,6 +90,7 @@
 | 11  |     | [Baekjoon-13023 ABCDE](./src/DFS/P13023)               |      |
 | 12  |     | [SWEA-5215 햄버거 다이어트](./src/DFS/swea5215)            |      |
 | 13  |     | [Baekjoon-3109 빵집](./src/DFS/P3109)                   |      |
+| 14  |     | [Baekjoon-1987 알파벳](./src/DFS/P1987)                  |      |
 
 ### BFS
 

src/DFS/P1987/Main.java

@@ -0,0 +1,48 @@
+package DFS.P1987;
+
+import java.io.*;
+import java.util.StringTokenizer;
+
+public class Main {
+
+    static int R, C, max;
+    static char[][] map;
+    static boolean[] visited = new boolean[26];
+
+    static int[] di = {-1, 0, 1, 0};
+    static int[] dj = {0, 1, 0, -1};
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/DFS/P1987/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        R = Integer.parseInt(st.nextToken());
+        C = Integer.parseInt(st.nextToken());
+
+        map = new char[R][C];
+        for (int i = 0; i < R; i++) map[i] = br.readLine().toCharArray();
+
+        visited[map[0][0]-'A'] = true;
+        dfs(0, 0, 1);
+        System.out.println(max);
+    }
+
+    static void dfs(int i, int j, int cnt) {
+        for (int t = 0; t < 4; t++) {
+            int to_i = i + di[t];
+            int to_j = j + dj[t];
+
+            if (isValidPath(to_i, to_j) && !visited[map[to_i][to_j]-'A']) {
+                visited[map[to_i][to_j]-'A'] = true;
+                dfs(to_i, to_j, cnt+1);
+                visited[map[to_i][to_j]-'A'] = false;
+            }
+        }
+        max = Math.max(max, cnt);
+    }
+
+    static boolean isValidPath(int i, int j) {
+        return 0 <= i && i < R && 0 <= j && j < C;
+    }
+}

src/DFS/P1987/README.md

@@ -0,0 +1,5 @@
+## [baekjoon-1987] 알파벳
+
+![image](https://user-images.githubusercontent.com/22045163/108330570-15c25580-7211-11eb-8be2-c4fee4e06cf6.png)
+
+![image](https://user-images.githubusercontent.com/22045163/108330608-22df4480-7211-11eb-9336-32e4fd4d72af.png)

src/DFS/P1987/input.txt

@@ -0,0 +1,3 @@
+2 4
+CATB
+BDCB