BOJ - 6189 - Munching

import sys
from collections import deque

dx = [0, 0, 1, -1]
dy = [1, -1, 0, 0]

def BFS(sx, sy, ex, ey, matrix, R, C):
    dq = deque()
    dq.append((sx, sy, 0))
    visit = [[False for _ in range(C)] for _ in range(R)]
    visit[sx][sy] = True

    while dq:
        x, y, w = dq.popleft()

        if x == ex and y == ey:
            return w

        for k in range(4):
            nx, ny = x + dx[k], y + dy[k]
            if 0 <= nx < R and 0 <= ny < C:
                if visit[nx][ny] == False and (matrix[nx][ny] == '.' or matrix[nx][ny] == 'C'):
                    visit[nx][ny] = True
                    dq.append((nx, ny, w + 1))

    return -1

def solution():
    R, C = map(int, sys.stdin.readline().split())

    matrix = []
    for _ in range(R):
        matrix.append(list(sys.stdin.readline().strip()))

    sx, sy, dx, dy = 0, 0, 0, 0
    for i in range(R):
        for j in range(C):
            if matrix[i][j] == 'B':
                sx, sy = i, j
            elif matrix[i][j] == 'C':
                dx, dy = i, j

    print(BFS(sx, sy, dx, dy, matrix, R, C))

solution()

https://www.acmicpc.net/problem/6189