[백준/JAVA] 1987번 : 알파벳

📖  문제 링크

https://www.acmicpc.net/problem/1987

1987번: 알파벳

 

 

✅  최종 코드

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main_BJ_1987_알파벳3 {
	
	static int R, C, cnt;
	static int[][] board;
	static boolean[] alphabet = new boolean[26];
	static int[] dx = { -1, 0, 1,  0};	//상 우 하 좌
	static int[] dy = {  0, 1, 0, -1};
	static int max = Integer.MIN_VALUE;
	
	public static void main(String[] args) throws Exception {
		
		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 int[R][C];
		
		for (int i = 0; i < R; i++) {
			String str = br.readLine();
			for (int j = 0; j < C; j++) {
				board[i][j] = str.charAt(j) - 'A';
			}
		}
		
		dfs(0, 0, 1);
		System.out.println(max);
		
		
		
		
	}//main
	
	

	private static void dfs(int x, int y, int cnt) {
		
		if(max == 26)	return;
		
		alphabet[board[x][y]] = true;
		
		int nx, ny;
		
		for(int i=0;i<4;i++) {
			
			nx = x + dx[i];
			ny = y + dy[i];
			
			if(nx >= 0 && nx < R && ny >= 0 && ny < C && !alphabet[board[nx][ny]]) {
				alphabet[board[nx][ny]] = true;
				dfs(nx, ny, cnt+1);
				alphabet[board[nx][ny]] = false;
				
			}
		
			
		}
		
		max = Math.max(max, cnt);
		return;
		
		
		
		
	}//end dfs
	
}//end class