[acmicpc] 1987. 알파벳(python)

dfs, 알파벳 배열 생성 후 방문 체크

import sys
input=sys.stdin.readline

R,C=map(int,input().split())
board=[list(input().strip()) for _ in range(R)]
dirs=[(1,0),(0,1),(-1,0),(0,-1)]
alpha=[0]*26
answer=0
def dfs(row,col,cnt):
    global answer
    answer=max(answer,cnt)
    for i in range(4):
        nr,nc=row+dirs[i][0],col+dirs[i][1]
        if 0<=nr<R and 0<=nc<C:
            next=ord(board[nr][nc])-65
            if alpha[next]==0:
                alpha[next]=1
                dfs(nr,nc,cnt+1)
                alpha[next] = 0
alpha[ord(board[0][0])-65]=1
dfs(0,0,1)
print(answer)