python代码

from collections import deque

n, m = map(int, input().split())
L = []
dx = [0, 0, -1, 1]
dy = [-1, 1, 0, 0]

for i in range(n):
    res = list(map(int, input().split()))
    L.append(res)

def getNeighbors(s):
    x = s[0]
    y = s[1]
    res = []
    for i in range(4):
        new_x = x + dx[i]
        new_y = y + dy[i]
        if 0 <= new_x < n and 0 <= new_y < m:
            if L[new_x][new_y] == 0:
                res.append((new_x, new_y))
    return res

def bfs(L, start_x, start_y):
    q = deque([(start_x, start_y)])
    visit = set()
    visit.add((start_x, start_y))
    step = 0
    while q:
        sz = len(q)
        for _ in range(sz):
            cur = q.popleft()
            if cur == (n - 1, m - 1):
                return step
            for to in getNeighbors(cur):
                if to not in visit:
                    q.append(to)
                    visit.add(to)
        step += 1
    return -1

print(bfs(L, 0, 0))