BOJ_1987 : 알파벳

Author: spring0913

week14/BOJ_1987(알파벳).java

@@ -0,0 +1,53 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    private static int R, C;
+    private static char[][] board;
+    private static boolean[][] visited;
+    private static boolean[] check;
+    private static int[] dh = {-1, 0, 1, 0};
+    private static int[] dw = {0, 1, 0, -1};
+    private static int answer = 0;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        R = Integer.parseInt(st.nextToken());
+        C = Integer.parseInt(st.nextToken());
+        board = new char[R][C];
+        visited = new boolean[R][C];
+        check = new boolean[30];
+        for(int i=0; i<R; i++) {
+            String input = br.readLine();
+            for(int j=0; j<C; j++) {
+                board[i][j] = input.charAt(j);
+            }
+        }
+        visited[0][0] = true;
+        check[board[0][0] - 'A'] = true;
+        dfs(0, 0, 1);
+        System.out.println(answer);
+    }
+
+    public static void dfs(int h, int w, int depth) {
+        if(depth > R*C) {
+            return;
+        }
+        answer = Math.max(answer, depth);
+
+        for(int i=0; i<4; i++) {
+            int nextH = h + dh[i];
+            int nextW = w + dw[i];
+            if(nextH >= 0 && nextH < R && nextW >=0 && nextW < C) {
+                int index = board[nextH][nextW] - 'A';
+                if(!visited[nextH][nextW] & !check[index]) {
+                    check[index] = true;
+                    dfs(nextH, nextW, depth+1);
+                    check[index] = false;
+                }
+            }
+        }
+    }
+}