Problem:


Score : 100 points

Problem Statement

There is a grid with H horizontal rows and W vertical columns.
Let (i, j) denote the square at the i-th row from the top and the j-th column from the left.

For each i and j (1 \leq i \leq H, 1 \leq j \leq W), Square (i, j) is described by a character a_{i, j}.
If a_{i, j} is ., Square (i, j) is an empty square; if a_{i, j} is #, Square (i, j) is a wall square.
It is guaranteed that Squares (1, 1) and (H, W) are empty squares.

Taro will start from Square (1, 1) and reach (H, W) by repeatedly moving right or down to an adjacent empty square.

Find the number of Taro's paths from Square (1, 1) to (H, W).
As the answer can be extremely large, find the count modulo 10^9 + 7.

Constraints

H and W are integers.

2 \leq H, W \leq 1000

a_{i, j} is . or #.

Squares (1, 1) and (H, W) are empty squares.

Input

Input is given from Standard Input in the following format:

H W
a_{1, 1}\ldotsa_{1, W}
:
a_{H, 1}\ldotsa_{H, W}

Output

Print the number of Taro's paths from Square (1, 1) to (H, W), modulo 10^9 + 7.

Sample Input 1

3 4
...#
.#..
....

Sample Output 1

3

There are three paths as follows:

Sample Input 2

5 2
..
#.
..
.#
..

Sample Output 2

0

There may be no paths.

Sample Input 3

5 5
..#..
.....
#...#
.....
..#..

Sample Output 3

24

Sample Input 4

20 20
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................

Sample Output 4

345263555

Be sure to print the count modulo 10^9 + 7.



Sample input:
3 4
...#
.#..
....


Sample output:
3

Submission status: Accepted

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

    """ convenient functions
    # for i, a in enumerate(iterable)
    # q, mod = divmod(a, b)
    # divmod(x, y) returns the tuple (x//y, x%y)
    # Higher-order function: reduce(operator.mul, xyz_count, 1)
    # manage median(s) using two heapq https://atcoder.jp/contests/abc127/tasks/abc127_f
    """

    """convenient decorator
    # @functools.lru_cache():
    # to facilitate use of recursive function
        # ex:
        # from functools import lru_cache
        # import sys
        # sys.setrecursionlimit(10**9)
        # @lru_cache(maxsize=None)
        # def fib(n):
        #     if n < 2:
        #         return n
        #     return fib(n-1) + fib(n-2)
        # print(fib(1000))
    """
    
    # import numpy as np
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product # https://docs.python.org/ja/3/library/itertools.html
    # accumulate() returns iterator! to get list: list(accumulate())
    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 = []  # prime factor
        b, e = 2, 0  # base, exponent
        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
        """
        # TODO: How should I do when n - r is negative?
        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 # https://docs.python.org/ja/3/library/collections.html#collections.deque
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest # https://docs.python.org/ja/3/library/heapq.html
    from copy import deepcopy, copy # https://docs.python.org/ja/3/library/copy.html
    import operator
    from operator import itemgetter #sort 
    # ex1: List.sort(key=itemgetter(1))
    # ex2: sorted(tuples, key=itemgetter(1,2))
    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 # Deprecated since version 3.5: Use math.gcd() instead.
    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)
    
    # first create factorial_list
    # fac_list = mod_factorial_list(n)
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    modpow = lambda a, n, p = MOD: pow(a, n, p) # Recursive function in python is slow!
    def modinv(a, p = MOD):
        # evaluate reciprocal using Fermat's little theorem:
        # a**(p-1) is identical to 1 (mod p) when a and p is coprime
        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):
        # fac_list = modfactorial_list(100)
        # print(modcomb(100, 5, modfactorial_list(100)))
        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]

    # Graph: https://en.wikipedia.org/wiki/Directed_graph
    # Bellman-Ford: O(|V||E|). Use this if there exists an edge with negative length in the graph
    # After N steps, the shortest path has converded if there doesn't exist an cycle of edges with negative
    # Watch out: d[N] == d[2*N] doesn't necessarily mean the graph doesn't have negative cycle
    # ref: https://www.youtube.com/watch?v=1Z6ofKN03_Y

    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]

    """ initialize variables and set inputs
    # initialize variables
        # to initialize list, use [0] * n
        # to initialize two dimentional array:
            # ex) [[0] * N for _ in range(N)]
            # ex2) dp = [[0] * (N+1) for _ in range(W*2)]
    # set inputs
        # put inputs between specific values (almost as quickly)
        # ex) S = [-INF] + [int(r()) for _ in range(A)] + [INF]
        # open(0).read() is sometimes useful:
        # ex) n, m, *x = map(int, open(0).read().split())
        #     min(x[::2]) - max(x[1::2])
        # ex2) *x, = map(int, open(0).read().split())
        #     don't forget to add comma after *x if only one variable is used
    # preprocessing
        # transpose = [x for x in zip(*data)]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [(1, 4, 7), (2, 5, 8), (3, 6, 9)]
        # flat = [flatten for inner in data for flatten in inner]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [1, 2, 3, 4, 5, 6, 7, 8, 9]
    # calculate and output
        # output pattern
        # ex1) print(*l) => when l = [2, 5, 6], printed 2 5 6
    """

    # functions to read input
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    R = lambda: list(map(int, r().split()))
    Rmap = lambda: map(int, r().split())
    Rfloat = lambda: list(map(float, r().split()))
    Rtuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    # single int: int(r())
    # single string: r()
    # single float: float(r())
    # line int: R()
    # line string: r().split()
    # line (str, int, int): [j if i == 0 else int(j) for i, j in enumerate(r().split())]
    # lines int: [R() for _ in range(n)]
    """

    # for test
    if sample_file:
        sys.stdin = open(sample_file)
        
    # ----------------------------------
    # main

    H, W = R()
    A = [r() for _ in range(H)]
    # watasu dp
    dp = [[0]*(W+H+2) for _ in range(H+W+2)]
    dp[0][0] = 1
    for i in range(H+W+1):
        for w in range(i+1):
            h = i -w
            if w <= W-1 and h <= H-1 and A[h][w] == '#':
                continue
            dp[h+1][w] = (dp[h][w] + dp[h+1][w])%(10**9+7)
            dp[h][w+1] = (dp[h][w] + dp[h][w+1])%(10**9+7)
    print(dp[H-1][W-1]%(10**9+7))
    
    # to finish code, use return instead of exit()
    # end of main
    # ----------------------------------

    """memo: how to use defaultdict of list
    # initialize
    Dic = defaultdict(list)
    # append / extend
    Dic[x].append(y)
    # three methods for loop: keys(), values(), items()
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    # to make binary digits text
    >>> a = 5
    >>> bin_str_a = format(a, '#06b')
    >>> print(bin_str_a)
    0b0101 # first 2 strings (='0b') indicates it is binary
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
import sys
input = lambda: sys.stdin.readline().rstrip()
tdlist = lambda i, j, value=0: [[value] * j for _ in range(i)]
MOD = 10**9+7

h, w = map(int, input().split())
grid = tdlist(h, w)

for i in range(h):
    for j, x in enumerate(input()):
        grid[i][j] = -1 if x == "#" else 0

for i in range(h):
    if grid[i][0] == -1: break
    grid[i][0] = 1

for j in range(w):
    if grid[0][j] == -1: break
    grid[0][j] = 1

for i in range(1, h):
    for j in range(1, w):
        if grid[i][j] == -1: continue
        a = 0 if grid[i-1][j] == -1 else grid[i-1][j]
        b = 0 if grid[i][j-1] == -1 else grid[i][j-1]
        grid[i][j] = (a + b) % MOD

print(grid[h-1][w-1] % MOD)

Submission status: Accepted

Solution code:
MOD = 10**9+7
n, m = map(int, input().split())
a = ['' for _ in range(n)]
for i in range(n):
    a[i] = input()
dp = [[0] * m for _ in range(n)]
dp[0][0] = 1
for i in range(n):
    for j in range(m):
        if a[i][j] == '.':
            if i - 1 >= 0:
                dp[i][j] = (dp[i][j] + dp[i - 1][j]) % MOD
            if j - 1 >= 0:
                dp[i][j] = (dp[i][j] + dp[i][j - 1]) % MOD
print(dp[-1][-1])

Submission status: Accepted

Solution code:
import sys
import collections


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    h, w = list(map(int, input().rstrip('\n').split()))
    a = [list(str(input().rstrip('\n'))) for _ in range(h)]
    for i in range(h):
        for j in range(w):
            if a[i][j] == ".":
                a[i][j] = 0
            else:
                a[i][j] = -1

    a[0][0] = 1
    ql = [[0, 0, 0]]
    ql = collections.deque(ql)
    while True:
        if len(ql) != 0:
            cost, x, y = ql.popleft()
            for xv, yv in [[x + 1, y], [x, y + 1]]:
                if 0 <= xv < h and 0 <= yv < w:
                    if a[xv][yv] == 0:
                        ql.append([cost + 1, xv, yv])
                        a[xv][yv] += a[x][y]
                    elif a[xv][yv] != -1:
                        a[xv][yv] += a[x][y]
        else:
            break
    print(a[-1][-1] % mod)


if __name__ == '__main__':
    solve()

Submission status: Accepted

Solution code:
H, W = map(int,input().split())
A = [list(input()) for _ in range(H)]

dp = [[0] * (W+1) for _ in range(H+1)]

for i in range(1,H+1):
    for j in range(1,W+1):
        if i == 1 and j == 1:
            dp[i][j] = 1
        else:
            if A[i-1][j-1] == '.':
                dp[i][j] = dp[i-1][j] + dp[i][j-1]
            elif A[i-1][j-1] == '#':
                dp[i][j] = 0

print((dp[-1][-1])%(10**9+7))

Submission status: Accepted

Solution code:
mod = 10**9 + 7
h, w = map(int, input().split())
grid = []
for _ in range(h):
    tem = list(input())
    grid.append(tem)

dp = [[0 for i in range(w)] for j in range(h)]
for i in range(h):
    for j in range(w):
        if grid[i][j] != '#':
            if i == 0 and j == 0:
                dp[i][j] = 1
            elif i == 0 and grid[i][j-1] != '#':
                dp[i][j] = dp[i][j - 1]
            elif j == 0 and grid[i - 1][j] != '#':
                dp[i][j] = dp[i - 1][j]
            else:
                dp[i][j] = (dp[i - 1][j] + dp[i][j - 1]) % (mod)

print(dp[-1][-1])

Submission status: Accepted

Solution code:
import sys
sys.setrecursionlimit(10**5+100)
MOD = 10**9+7

H, W = list(map(int, input().split()))
a = [input() for _ in range(H)]

dp = [[-1]*W for _ in range(H)]
def rec(h, w):
    if dp[h][w]!=-1:
        return dp[h][w]
    else:
        dp[h][w] = 0
        if h<H-1:
            if a[h+1][w]!='#':
                dp[h][w] = rec(h+1, w)%MOD
        if w<W-1:
            if a[h][w+1]!='#':
                dp[h][w] += rec(h, w+1)%MOD
        if h==H-1 and w==W-1:
            dp[h][w] = 1
        return dp[h][w]%MOD

print(rec(0,0))

Submission status: Accepted

Solution code:
H, W = map(int, input().split())
mod = 10 ** 9 + 7
A = []
for _ in range(H):
    a = input()
    A.append(a)

dp = [[0] * W for _ in range(H)]
dp[0][0] = 1
for i in range(H):
    for j in range(W):
        if i + 1 < H and A[i+1][j] == ".":
            dp[i+1][j] += dp[i][j]
            dp[i+1][j] %= mod
        if j + 1 < W and A[i][j+1] == ".":
            dp[i][j+1] += dp[i][j]
            dp[i][j+1] %= mod

print(dp[-1][-1])

Submission status: Accepted

Solution code:
import sys
import collections


def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    h, w = list(map(int, readline().split()))
    a = [list(str(readline().rstrip().decode('utf-8'))) for _ in range(h)]
    for i in range(h):
        for j in range(w):
            if a[i][j] == "#":
                a[i][j] = -1
            else:
                a[i][j] = 0
    a[0][0] = 1
    ql = [[0, 0, 0]]
    ql = collections.deque(ql)
    while True:
        if len(ql) != 0:
            cost, x, y = ql.popleft()
            for xv, yv in [[x + 1, y], [x, y + 1]]:
                if 0 <= xv < h and 0 <= yv < w:
                    if a[xv][yv] == 0:
                        ql.append([cost + 1, xv, yv])
                        a[xv][yv] += a[x][y]
                    else:
                        if a[xv][yv] != -1:
                            a[xv][yv] += a[x][y]
                            a[xv][yv] %= mod
        else:
            break
    print(a[h-1][w-1] % mod)


if __name__ == '__main__':
    solve()

Submission status: Accepted

Solution code:
n,h = map(int,input().split())
A = [list(input()) for i in range(n)] 
lim = 10 **9 +7
c = [[0 for _ in range(h)] for _ in range(n)] 

for i in range(0,n):
    for j in range(0,h):
        if not A[i][j] =="#":
            if i ==0 and j ==0:
                c[i][j] = 1
            elif i-1<0:
                c[i][j] = c[i][j-1]
            elif j-1<0:
                c[i][j] = c[i-1][j] 
            else:
                c[i][j] = c[i-1][j] + c[i][j-1]
        c[i][j] %= lim
print(c[-1][-1])

Submission status: Accepted

Solution code:
def p_h():
    h, w = map(int, input().split())
    dp = []
    for _ in range(h):
        dp.append(list(map(int, input().replace(".", "0 ").replace("#", "-1 ").split())))
    dp[0][0] = 1
    mod = 10**9 + 7

    for i in range(h):
        for j in range(w):
            if j < w - 1 and dp[i][j + 1] != -1 and dp[i][j] != -1:
                dp[i][j + 1] += dp[i][j]
                dp[i][j + 1] %= mod
            if i < h - 1 and dp[i + 1][j] != -1 and dp[i][j] != -1:
                dp[i + 1][j] += dp[i][j]
                dp[i + 1][j] %= mod

    print(dp[-1][-1])


if __name__ == '__main__':
    p_h()

Submission status: Accepted

Solution code:
h,w=map(int,input().split())
g=[input() for _ in range(h)]

dp=[[0]*w for _ in range(h)]

for i in range(h):
    for j in range(w):
        if g[i][j]=="#":
            continue
        if i==0 and j==0:
            dp[i][j]=1
        elif i==0:
            dp[i][j]=dp[i][j-1]
        elif j==0:
            dp[i][j]=dp[i-1][j]
        else:
            dp[i][j]=dp[i-1][j]+dp[i][j-1]

print(dp[h-1][w-1]%(10**9+7))

Submission status: Accepted

Solution code:
import sys
#input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)
mod = 10**9+7
H, W = map(int, input().split())
a = [list(input()) for _ in range(H)]
dp = [[0]*W for _ in range(H)]
dp[0][0] = 1
for i in range(H):
    for j in range(W):
        if a[i][j] == '#':
            continue
        if i<H-1:
            dp[i+1][j] += dp[i][j]
            dp[i+1][j]%=mod
        if j<W-1:
            dp[i][j+1] += dp[i][j]
            dp[i][j+1]%=mod
print(dp[-1][-1])

Submission status: Accepted

Solution code:
H,W = map(int,input().split())
Data = []
MOD = 10**9+7
for _ in range(H):
    Data.append(input())
DP = [[-1]*(W) for _ in range(H)]

for h in range(H):
    for w in range(W):
        if h == 0 and w == 0:
            DP[h][w] = 1 
        elif Data[h][w] == '.':
            path = 0
            if w > 0 and DP[h][w-1] != -1:
                path += DP[h][w-1]
            if h > 0 and DP[h-1][w] != -1:
                path += DP[h-1][w]
            DP[h][w]= path % MOD


print(DP[H-1][W-1])

Submission status: Accepted

Solution code:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append(input())
mod = 10**9+7

dp = [[0 for _ in range(W)] for _ in range(H)]
dp[0][0] = 1
for i in range(H):
    for j in range(W):
        if i == j == 0:
            continue
        if grid[i][j] == '.':
            upper = dp[i-1][j] if i > 0 else 0
            left = dp[i][j-1] if j > 0 else 0
            dp[i][j] = (upper + left) % mod

print(dp[-1][-1])

Submission status: Accepted

Solution code:
import sys


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    h, w = list(map(int, input().rstrip('\n').split()))
    a = [list(str(input().rstrip('\n'))) for _ in range(h)]
    dp = [[0] * w for _ in range(h)]
    for i in range(h):
        for j in range(w):
            if a[i][j] == "#":
                dp[i][j] = 0
            elif i == 0 and j == 0:
                dp[i][j] = 1
            elif i == 0:
                dp[i][j] = dp[i][j-1]
            elif j == 0:
                dp[i][j] = dp[i-1][j]
            else:
                dp[i][j] = (dp[i-1][j] + dp[i][j-1]) % mod
    print(dp[-1][-1])


if __name__ == '__main__':
    solve()

Submission status: Accepted

Solution code:
H,W=map(int,input().split())
a=[]
dp=[[0 for i in range(W)] for j in range(H)]
dp[0][0]=1
for i  in range(H):
    a.append(list(input()))
for i in range(H):
    for j in range(W):
        u=0
        l=0
        if j>0 and a[i][j-1]!='#':
            l=dp[i][j-1]
        if i>0 and a[i-1][j]!='#':
            u=dp[i-1][j]
        dp[i][j]+=u+l
print(dp[H-1][W-1]%(10**9+7))

Submission status: Accepted

Solution code:
H,W = map(int,input().split())
grid = [input() for i in range(H)]

dp = [[0 for j in range(W)] for i in range(H)]

for i in range(H):
    if grid[i][0] == '#':
        break
    dp[i][0] = 1

for j in range(W):
    if grid[0][j] == '#':
        break
    dp[0][j] = 1

for i in range(1,H):
    for j in range(1,W):
        if grid[i][j] == '.':
            dp[i][j] = dp[i-1][j]+dp[i][j-1]
            dp[i][j] %= 1000000007

print(dp[H-1][W-1]%1000000007)

Submission status: Accepted

Solution code:
def Grid(root): # マップxを最短経路で進む場合の数
    mod=10**9+7
    
    dp=[[0 for _ in range(w)] for _ in range(h)]
    dp[0][0]=1
    for i in range(h):
        for j in range(w):
            if root[i][j]=="#":
                dp[i][j]=0
            elif i>=1 and j>=1 and root[i-1][j]=="." and root[i][j-1]==".":
                dp[i][j]=( dp[i-1][j]+dp[i][j-1] ) % mod
            elif  i>=1 and j>=1 and root[i-1][j]=="#" and root[i][j-1]==".":
                dp[i][j]=( dp[i][j-1] ) % mod
            elif  i>=1 and j>=1 and root[i-1][j]=="." and root[i][j-1]=="#":
                dp[i][j]=( dp[i-1][j] ) % mod
            elif i==0 and j>=1:
                dp[0][j]=dp[0][j-1]
            elif i>=1 and j==0:
                dp[i][0]=dp[i-1][0]
    print(dp[h-1][w-1])

def main():
    global h,w
    h,w = map(int,input().split())
    root=[]
    for _ in range(h):
        root.append(list(input()))
    Grid(root)

    
if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
h,w = map(int,input().split())
grid1 = [['#'] * (w+2) for i in range(h+2)]
grid2 = [[0] * (w+2) for i in range(h+2)]
for i in range(h):
  grid1[i+1][1:-1] = list(input())
for i in range(1,h+1):
  for j in range(1,w+1):
    if i == j == 1:
      grid2[i][j] = 1
    elif grid1[i][j] == '.':
      grid2[i][j] = (grid2[i-1][j] + grid2[i][j-1]) % (10**9+7)
print(grid2[h][w])

Submission status: Accepted

Solution code:
import sys
readline = sys.stdin.buffer.readline
# ord('.') == 46

def main():
    H, W = map(int, readline().split())
    a = readline()
    k = a.find(b'#')
    if k == -1:
        k = W
    v = [1] * k + [0] * (W - k)

    for m in range(1, H):
        a = readline()
        v[0] = t = v[0] if a[0] == 46 else 0
        if m % 80 == 0:
            for j, u, aa in zip(range(1, W), v[1:], a[1:W]):
                v[j] = t = (u + t) % 1000000007 if aa == 46 else 0
        else:
            for j, u, aa in zip(range(1, W), v[1:], a[1:W]):
                v[j] = t = (u + t) if aa == 46 else 0
    print(v[-1] % 1000000007)


main()

Submission status: Accepted

Solution code:
import sys
readline = sys.stdin.buffer.readline
# ord('.') == 46

def main():
    H, W = map(int, readline().split())
    a = readline()
    k = a.find(b'#')
    if k == -1:
        k = W
    v = [1] * k + [0] * (W - k)
    u = [0] * W

    for _ in range(1, H):
        a = readline()
        u, v = v, u
        v[0] = t = u[0] if a[0] == 46 else 0
        for j, uu, aa in zip(range(1, W), u[1:], a[1:]):
            v[j] = t = uu + t if aa == 46 else 0
    print(v[-1] % (10 ** 9 + 7))


main()

Submission status: Accepted

Solution code:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

MOD = 10**9 + 7

H,W = map(int,readline().split())
A = np.frombuffer(read(),'S1').reshape(H,-1)[:,:W]

dp = np.zeros(W,np.int64)
dp[0] = 1

for h in range(H):
    wall = (A[h] == b'#')
    dp[wall] = 0
    np.cumsum(dp,out=dp)
    dp -= np.maximum.accumulate(dp*wall)
    dp %= MOD

answer = dp[-1]
print(answer)

Submission status: Accepted

Solution code:
def main():
    H, W = map(int, input().split())
    a = input()
    k = a.find('#')
    if k == -1:
        k = W
    v = [1] * k + [0] * (W - k)
    u = [0] * W

    for _ in range(1, H):
        a = input()
        u, v = v, u
        v[0] = t = u[0] if a[0] == '.' else 0
        for j, uu, aa in zip(range(1, W), u[1:], a[1:]):
            v[j] = t = uu + t if aa == '.' else 0
    print(v[-1] % (10 ** 9 + 7))


main()