Problem:
 Score : 400 points    Problem Statement A maze is composed of a grid of H \times W squares - H vertical, W horizontal.  The square at the i -th row from the top and the j -th column from the left - (i,j) - is a wall if S_{ij} is # and a road if S_{ij} is . .  There is a magician in (C_h,C_w) . He can do the following two kinds of moves:   Move A: Walk to a road square that is vertically or horizontally adjacent to the square he is currently in.  Move B: Use magic to warp himself to a road square in the 5\times 5 area centered at the square he is currently in.   In either case, he cannot go out of the maze.  At least how many times does he need to use the magic to reach (D_h, D_w) ?      Constraints  1 \leq H,W \leq 10^3  1 \leq C_h,D_h \leq H  1 \leq C_w,D_w \leq W  S_{ij} is # or . .  S_{C_h C_w} and S_{D_h D_w} are . .  (C_h,C_w) \neq (D_h,D_w)         Input Input is given from Standard Input in the following format:  H  W  C_h  C_w  D_h  D_w  S_{11}\ldots S_{1W}  \vdots  S_{H1}\ldots S_{HW}       Output Print the minimum number of times the magician needs to use the magic. If he cannot reach (D_h,D_w) , print -1 instead.        Sample Input 1 4 4
1 1
4 4
..#.
..#.
.#..
.#..      Sample Output 1 1  For example, by walking to (2,2) and then using the magic to travel to (4,4) , just one use of magic is enough.  Note that he cannot walk diagonally.       Sample Input 2 4 4
1 4
4 1
.##.
####
####
.##.      Sample Output 2 -1  He cannot move from there.       Sample Input 3 4 4
2 2
3 3
....
....
....
....      Sample Output 3 0  No use of magic is needed.       Sample Input 4 4 5
1 2
2 5
#.###
####.
#..##
#..##      Sample Output 4 2

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product, combinations_with_replacement 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):   
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd 
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    AtoZ = list('abcdefghijklmnopqrsruvwxyz') 
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    class SegTree:
        """
        ref: https://qiita.com/takayg1/items/c811bd07c21923d7ec69
        init(init_val, ide_ele): 配列init_valで初期化 O(N)
        update(k, x): k番目の値をxに更新 O(logN)
        query(l, r): 区間[l, r)をsegfuncしたものを返す O(logN)
        """
        def __init__(self, init_val, segfunc, ide_ele):
            """
            init_val: 配列の初期値
            segfunc: 区間にしたい操作
            ide_ele: 単位元
            n: 要素数
            num: n以上の最小の2のべき乗
            tree: セグメント木(1-index)
            """
            n = len(init_val)
            self.segfunc = segfunc
            self.ide_ele = ide_ele
            self.num = 1 << (n - 1).bit_length()
            self.tree = [ide_ele] * 2 * self.num
            
            for i in range(n):
                self.tree[self.num + i] = init_val[i]
            
            for i in range(self.num - 1, 0, -1):
                self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

        def update(self, k, x):
            """
            k番目の値をxに更新
            k: index(0-index)
            x: update value
            """
            k += self.num
            self.tree[k] = x
            while k > 1:
                self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
                k >>= 1

        def query(self, l, r):
            """
            [l, r)のsegfuncしたものを得る
            l: index(0-index)
            r: index(0-index)
            """
            res = self.ide_ele
            l += self.num
            r += self.num
            while l < r:
                if l & 1:
                    res = self.segfunc(res, self.tree[l])
                    l += 1
                if r & 1:
                    res = self.segfunc(res, self.tree[r - 1])
                l >>= 1
                r >>= 1
            return res

    
    
    
    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    
    def warshall_floyd(number_vertex, XYD, shift_one_for_vertex=False):
        
        
        
        
        
        d = [[float("inf")]*number_vertex for i in range(number_vertex)]
        for x, y, dist in XYD:
            if shift_one_for_vertex:
                x = x - 1
                y = y - 1
            d[x][y] = dist
            d[y][x] = dist
        for i in range(number_vertex):
            d[i][i] = 0 
        for k in range(number_vertex):
            for i in range(number_vertex):
                for j in range(number_vertex):
                    d[i][j] = min(d[i][j],d[i][k] + d[k][j])
        return d


    """ initialize variables and set inputs
    
        
        
            
            
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    r_float = lambda: float(r())
    R = lambda: list(map(int, r().split()))
    R_str = lambda: r().split()
    R_map = lambda: map(int, r().split())
    R_float = lambda: list(map(float, r().split()))
    R_tuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    H, W = R()
    Ch, Cw = R()
    Ch -= 1
    Cw -= 1
    Dh, Dw = R()
    Dh -= 1
    Dw -= 1
    
    S = [r() for _ in range(H)]
    arrived = [[0]*W for _ in range(H)]
    que = set()
    que_next = set()
    que.add((Ch, Cw))
    cnt = 0

    while True:
        while que:
            h, w = que.pop()
            jump = False
            if arrived[h][w] == 1:
                pass
            else:
                if h == Dh and w == Dw:
                    print(cnt)
                    return
                arrived[h][w] = 1
                for i, j in [(0, -1), (0, 1), (-1, 0), (1, 0)]:
                    if h+i < 0 or h+i > H-1 or w+j < 0 or w+j > W-1:
                        pass
                    elif arrived[h+i][w+j] == 1:
                        pass
                    elif S[h+i][w+j] != '
                        que.add((h+i, w+j))
                    elif jump==False: 
                        jump = True
                        for ii, jj in product(range(-2, 3), range(-2, 3)):
                            if ii == 0 and jj==0:
                                pass
                            elif h+ii < 0 or h+ii > H-1 or w+jj < 0 or w+jj > W-1:
                                pass
                            elif arrived[h+ii][w+jj] == 1:
                                pass
                            elif S[h+ii][w+jj] != '
                                que_next.add((h+ii, w+jj))
        
        cnt += 1
        que = que_next
        que_next = set()
        
        if not que:
            print(-1)
            return

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    


    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
import sys

class UnionFind():
    def __init__(self, n):
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return False
        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x
        return True

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

def solve():
    readline = sys.stdin.readline
    H, W = map(int, readline().split())
    ch, cw = map(int, readline().split())
    dh, dw = map(int, readline().split())
    S = ['
    for _ in range(H):
        S += ['
    S += ['
    H += 2
    W += 2

    uf = UnionFind(H*W)
    for i in range(H*W):
        if S[i] == '
            continue
        for d in [-W, -1, 1, W]:
            if S[i+d] == '.':
                uf.union(i, i+d)

    now = ch*(W) + cw
    goal = dh*(W) + dw
    
    
    if uf.same(now, goal):
        print(0)
        return
    ans = 0
    q = set()
    q.add(now) 
    next_area = set() 
    visited = [False] * (H*W)

    
    
    while True:
        while q:
            x = q.pop()
            if x == goal:
                print(ans)
                return
            visited[x] = True
            for dy in [-2*W, -W, 0, W, 2*W]:
                for dx in [-2, -1, 0, 1, 2]:
                    xx = x + dy + dx
                    if 0 <= xx < W*H and S[xx] == '.' and not visited[xx]:
                        if uf.same(x, xx):
                            q.add(xx)
                        else:
                            next_area.add(xx)
        if next_area:
            q = next_area
            next_area = set()
        else:
            print(-1)
            return 
        ans += 1

if __name__ == '__main__':
    solve()

Solution (Python):
from collections import deque

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)]



def clear_maze(h, w, ch, cw, dh, dw, S):
    visited = [[-1] * w for _ in range(h)]
    visited[ch - 1][cw - 1] = 0
    queue = deque([[ch - 1 , cw - 1]])
    m_queue = deque([])
    while queue or m_queue:
        if queue:
            y, x = queue.popleft()
        else:
            n_y, n_x, y, x = m_queue.popleft()
            if visited[n_y][n_x] != -1:
                continue
            visited[n_y][n_x] = visited[y][x] + 1
            y, x = n_y, n_x
        if [y, x] == [dh - 1, dw - 1]:
            return visited[y][x]
        num = 0
        for i, j in ([1, 0], [-1, 0], [0, 1], [0, -1]):
            n_y = y + i
            n_x = x + j
            if n_y >= 0 and n_y < h and n_x >= 0 and n_x < w and S[n_y][n_x] == '.':
                if visited[n_y][n_x] == -1:
                    visited[n_y][n_x] = visited[y][x]
                    queue.append([n_y, n_x])
                else:
                    if visited[y][x] < visited[n_y][n_x]:
                        queue.append([n_y, n_x])
                    visited[n_y][n_x] = min(visited[n_y][n_x], visited[y][x])
        for i in range(-2, 2 + 1):
            for j in range(-2, 2 + 1):
                if not [i, j] in ([1, 0], [-1, 0], [0, 0], [0, 1], [0, -1]):
                    n_y = y + i
                    n_x = x + j
                    if n_y >= 0 and n_y < h and n_x >= 0 and n_x < w and S[n_y][n_x] == '.':
                        if visited[n_y][n_x] == -1:
                            
                            m_queue.append([n_y, n_x, y, x])
                        
                            
                            
                            
    return -1

print(clear_maze(h, w, ch, cw, dh, dw, S))

Solution (Python):
from collections import deque
H, W = map(int, input().split())
cy, cx = map(int, input().split())
dy, dx = map(int, input().split())
cy -= 1
cx -= 1
dy -= 1
dx -= 1

S = [input() for _ in range(H)]

worps = [[float('inf')]*W for _ in range(H)]
used = [[False]*W for _ in range(H)]
q = deque([[cy, cx]])

worp = 0
while q:
    v = {}
    while q:
        y, x = q.popleft()
        used[y][x] = True
        worps[y][x] = min(worps[y][x], worp)

        for h in range(-2+y, 3+y):
            for w in range(-2+x, 3+x):
                if 0 <= h and h < H and 0 <= w and w < W and S[h][w] == ".":
                    v[(h, w)] = True

        for h, w in [[0, 1], [0, -1], [1, 0], [-1, 0]]:
            ny, nx = y+h, x+w
            if 0 <= ny and ny < H and 0 <= nx and nx < W:
                if not used[ny][nx] and S[ny][nx] == ".":
                    q.appendleft([ny, nx])

    worp += 1
    for h, w in v.keys():
        if not used[h][w]:
            q.appendleft([h, w])
            used[h][w] = True

ans = worps[dy][dx]
if ans != float('inf'):
    print(ans)
else:
    print(-1)

Solution (Python):
def dfs(xt, yt, S, V, w):
    B = set()
    while(len(S) > 0):
        xi, yi = S.pop()
        A = []
        for i in range(-2, 3):
            for j in range(-2, 3):
                if i == 0 and j == 0:
                    continue
                xj, yj = xi + i, yi + j
                if xj < 0 or len(V) <= xj or yj < 0 or len(V[0]) <= yj:
                    continue
                if -1 <= i <= 1 and -1 <= j <= 1 and i * j == 0:
                    A.append((xj, yj))
                else:
                    B.add((xj, yj))

        for xj, yj in A:
            if xj == xt and yj == yt:
                return False, B, V, w
            if V[xj][yj] > 0:
                V[xj][yj] = -1
                S.append((xj, yj))

    B_new = []
    for x, y in B:
        if x == xt and y == yt:
            return False, B, V, w + 1
        if V[x][y] > 0:
            V[x][y] = -1
            B_new.append((x, y))
    return True, B_new, V, w

h, w = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

s = [list(map(lambda x: int(x == '.'), list(input()))) for _ in range(h)]

flag = True
B = [(ch, cw)]
w = -1
s[ch][cw] = -1
while flag:
    flag, B, s, w = dfs(dh, dw, B, s, w + 1)
    if flag and len(B) == 0:
        print(-1)
        break
else:
    print(w)

Solution (Python):
from collections import deque
import sys

def input():
    return sys.stdin.readline().strip()

def main():
    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)]
    S[Ch-1][Cw-1] = 0

    def bfs(x,y):
        que = deque()
        que.append((x,y))

        while que:
            x,y = que.popleft()
            for dx,dy in ((-1,0),(1,0),(0,-1),(0,1)):
                sx = x + dx
                sy = y + dy
                if sx < 0 or sx >= W or sy < 0 or sy >= H:
                    continue
                if S[sy][sx] == '
                    continue
                if S[sy][sx] == '.':
                    S[sy][sx] = S[y][x]
                    que.appendleft((sx,sy))        
                else:
                    if S[sy][sx] > S[y][x]:
                        S[sy][sx] = S[y][x]
                        que.appendleft((sx,sy)) 
            for dx in range(-2,3):
                for dy in range(-2,3):
                    if (dx,dy) in ((-1,0),(1,0),(0,-1),(0,1),(0,0)):
                        continue
                    sx = x + dx
                    sy = y + dy
                    if sx < 0 or sx >= W or sy < 0 or sy >= H:
                        continue
                    if S[sy][sx] == '
                        continue
                    if S[sy][sx] == '.':
                        S[sy][sx] = S[y][x] + 1
                        que.append((sx,sy))
                    else:
                        if S[sy][sx] > S[y][x] + 1:
                            S[sy][sx] = S[y][x] + 1
                            que.append((sx,sy))     
    bfs(Cw-1,Ch-1)
    print(S[Dh-1][Dw-1] if S[Dh-1][Dw-1] != '.' else '-1')

if __name__ == "__main__":
    main()

Solution (Python):
def main():
    from collections import deque
    H, W = (int(i) for i in input().split())
    Ch, Cw = (int(i)-1 for i in input().split())
    Dh, Dw = (int(i)-1 for i in input().split())
    A = [input() for i in range(H)]
    V = [[-1]*W for i in range(H)]  
    d = ((1, 0), (0, 1), (-1, 0), (0, -1))

    def bfs_2d(sy, sx, v):
        que = deque()
        V[sy][sx] = v
        que.append((sy, sx))
        while que:
            uh, uw = que.popleft()
            for dy, dx in d:
                next_h = uh + dy
                next_w = uw + dx
                if not(0 <= next_h < H and 0 <= next_w < W):
                    continue
                if V[next_h][next_w] != -1:
                    continue
                if A[next_h][next_w] == '
                    continue
                V[next_h][next_w] = v
                que.append((next_h, next_w))

    vertex = 0
    for h in range(H):
        for w in range(W):
            if A[h][w] == "
                continue
            bfs_2d(h, w, vertex)
            vertex += 1

    G = [[] for _ in range(vertex)]
    used = [set() for _ in range(vertex)]
    for h in range(H):
        for w in range(W):
            if A[h][w] == "
                continue
            for dh in range(-2, 3):
                for dw in range(-2, 3):
                    if h + dh < 0 or H <= h + dh or w + dw < 0 or W <= w + dw:
                        continue
                    if A[h+dh][w+dw] == "
                        continue
                    if V[h][w] == V[h+dh][w+dw]:
                        continue
                    if V[h+dh][w+dw] in used[V[h][w]]:
                        continue
                    G[V[h][w]].append((V[h+dh][w+dw]))
                    used[V[h][w]].add((V[h+dh][w+dw]))

    
    

    
    

    s = V[Ch][Cw]
    g = V[Dh][Dw]
    que = deque([0])

    dist = [-1 for _ in range(vertex)]
    que = deque()
    dist[s] = 0
    que.append(s)
    while que:
        u = que.popleft()
        for v in G[u]:
            if dist[v] != -1:
                continue
            dist[v] = dist[u] + 1
            que.append(v)

    print(dist[g])


if __name__ == '__main__':
    main()

Solution (Python):

from collections import deque
H, W = map(int, input().split())
sx, sy = map(int, input().split())
sx -= 1
sy -= 1
gx, gy = map(int, input().split())
gx -= 1
gy -= 1
map = [list(input()) for i in range(H)]
cost_map = [[10**6]*W for i in range(H)]
d = deque()
cost_map[sx][sy] = 0
d.append([sx, sy])
while d:
    cx, cy = d.pop()
    if cx==gx and cy==gy:
        break
    ccost = cost_map[cx][cy]
    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        nx = cx + dx
        ny = cy + dy
        if 0<=nx<H and 0<=ny<W:
            if map[nx][ny]=="." and ccost < cost_map[nx][ny]:
                cost_map[nx][ny] = ccost
                d.append([nx, ny])
    dxy = [[-2, -2],[-2, -1],[-2, 0],[-2, 1],[-2, 2],
           [-1, -2],[-1, -1],[-1, 1],[-1, 2],
           [0, -2],[0, 2],
           [1, -2],[1, -1],[1, 1],[1, 2],
           [2, -2],[2, -1],[2, 0],[2, 1],[2, 2]]
    for dx, dy in dxy:
        nx = cx + dx
        ny = cy + dy
        if 0<=nx<H and 0<=ny<W:
            if map[nx][ny]=="." and (ccost + 1) < cost_map[nx][ny]:
                cost_map[nx][ny] = ccost + 1
                d.appendleft([nx, ny])
if cost_map[gx][gy] == 10**6:
    print("-1")
else:
    print(int(cost_map[gx][gy]))

Solution (Python):
from collections import deque
H, W = map(int, input().split())
cy, cx = map(int, input().split())
dy, dx = map(int, input().split())
cy -= 1
cx -= 1
dy -= 1
dx -= 1

S = [input() for _ in range(H)]

worps = [[float('inf')]*W for _ in range(H)]
used = [[False]*W for _ in range(H)]
q = deque([[cy, cx]])

worp = 0
while q:
    v = {}
    while q:
        y, x = q.popleft()
        used[y][x] = True
        worps[y][x] = min(worps[y][x], worp)

        for h in range(-2+y, 3+y):
            for w in range(-2+x, 3+x):
                if 0 <= h and h < H and 0 <= w and w < W and S[h][w] == ".":
                    v[(h, w)] = True

        for h, w in [[0, 1], [0, -1], [1, 0], [-1, 0]]:
            ny, nx = y+h, x+w
            if 0 <= ny and ny < H and 0 <= nx and nx < W:
                if not used[ny][nx] and S[ny][nx] == ".":
                    q.appendleft([ny, nx])

    worp += 1
    for h, w in v.keys():
        if not used[h][w]:
            q.appendleft([h, w])
            used[h][w] = True

ans = worps[dy][dx]
if ans != float('inf'):
    print(ans)
else:
    print(-1)