Buggy python submission (verdict: Time Limit Exceeded):
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

c = 0
q = [(ch, cw)]
while len(q) > 0:
    nq = []
    while len(q) > 0:
        i, j = q.pop()
        s[i][j] = c
        nq += [(i,j)]
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]


    while len(nq) > 0:
        i, j = nq.pop()
        for v in vec5:
            ii = i+v[0]
            jj = j+v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]
    c += 1
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])


Fixed submission:
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

c = 0
q = [(ch, cw)]
while len(q) > 0:
    nq = []
    while len(q) > 0:
        i, j = q.pop()
        s[i][j] = c
        nq += [(i,j)]
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]


    while len(nq) > 0:
        i, j = nq.pop()
        for v in vec5:
            ii = i+v[0]
            jj = j+v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]
    c += 1
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq, copy
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

lands = copy.deepcopy(s)
l = 0
def find_dot():
    for i in range(h):
        for j in range(w):
            if lands[i][j] == '.':
                return True, (i,j)
    return False, (0,0)

while True:
    b, (i,j) = find_dot()
    q = [(i,j)]
    if not b:
        break
    while len(q) > 0:
        i,j = q.pop()
        lands[i][j] = l
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and lands[ii][jj] == '.':
                q += [(ii, jj)]
    l += 1
q = [(0, (ch, cw))]
heapq.heapify(q)
while len(q) > 0:
    c, (i,j) = heapq.heappop(q)
    if s[i][j] != '.' and s[i][j] <= c:
        continue
    s[i][j] = c
    for v in vec:
        ii = i + v[0]
        jj = j + v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
            heapq.heappush(q, (c, (ii, jj)))
    for v in vec5:
        ii = i+v[0]
        jj = j+v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.' and lands[ii][jj] != lands[i][j]:
            heapq.heappush(q, (c+1, (ii, jj)))
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Fixed submission:
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

c = 0
q = [(ch, cw)]
while len(q) > 0:
    nq = []
    while len(q) > 0:
        i, j = q.pop()
        s[i][j] = c
        nq += [(i,j)]
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]


    while len(nq) > 0:
        i, j = nq.pop()
        for v in vec5:
            ii = i+v[0]
            jj = j+v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]
    c += 1
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]
q = [(0, (ch, cw))]
heapq.heapify(q)
while len(q) > 0:
    c, (i,j) = heapq.heappop(q)
    if s[i][j] != '.' and s[i][j] <= c:
        continue
    s[i][j] = c
    for v in vec:
        ii = i + v[0]
        jj = j + v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
            heapq.heappush(q, (c, (ii, jj)))
    for v in vec5:
        ii = i+v[0]
        jj = j+v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
            heapq.heappush(q, (c+1, (ii, jj)))
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Fixed submission:
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

c = 0
q = [(ch, cw)]
while len(q) > 0:
    nq = []
    while len(q) > 0:
        i, j = q.pop()
        s[i][j] = c
        nq += [(i,j)]
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]


    while len(nq) > 0:
        i, j = nq.pop()
        for v in vec5:
            ii = i+v[0]
            jj = j+v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]
    c += 1
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        vec5 += [(i,j)]

q = [(0, (ch, cw))]
heapq.heapify(q)
while len(q) > 0:
    c, (i,j) = heapq.heappop(q)
    if s[i][j] != '.' and s[i][j] != '#' and s[i][j] <= c:
        continue
    s[i][j] = c
    for v in vec:
        ii = i + v[0]
        jj = j + v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
            heapq.heappush(q, (c, (ii, jj)))
    for v in vec5:
        ii = i+v[0]
        jj = j+v[1]
        if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
            heapq.heappush(q, (c+1, (ii, jj)))
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])

Fixed submission:
h,w = map(int,input().split())
ch, cw = map(int,input().split())
dh, dw = map(int,input().split())
s = [list(input()) for _ in range(h)]
ch -= 1
cw -= 1
dh -= 1
dw -= 1
vec5 = []
vec = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(-2, 3):
    for j in range(-2, 3):
        if abs(i) + abs(j) < 2:
            continue
        vec5 += [(i,j)]

c = 0
q = [(ch, cw)]
while len(q) > 0:
    nq = []
    while len(q) > 0:
        i, j = q.pop()
        s[i][j] = c
        nq += [(i,j)]
        for v in vec:
            ii = i + v[0]
            jj = j + v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]


    while len(nq) > 0:
        i, j = nq.pop()
        for v in vec5:
            ii = i+v[0]
            jj = j+v[1]
            if 0 <= ii < h and 0 <= jj < w and s[ii][jj] == '.':
                q += [(ii, jj)]
    c += 1
if s[dh][dw] == '.':
    print(-1)
else:
    print(s[dh][dw])