Problem:


Score : 300 points

Problem Statement

There is a staircase with N steps. Takahashi is now standing at the foot of the stairs, that is, on the 0-th step.
He can climb up one or two steps at a time.

However, the treads of the a_1-th, a_2-th, a_3-th, \ldots, a_M-th steps are broken, so it is dangerous to set foot on those steps.

How many are there to climb up to the top step, that is, the N-th step, without setting foot on the broken steps?
Find the count modulo 1\ 000\ 000\ 007.

Constraints

1 \leq N \leq 10^5

0 \leq M \leq N-1

1 \leq a_1 < a_2 <  ...  < a_M \leq N-1

Input

Input is given from Standard Input in the following format:

N M
a_1
a_2
 .
 .
 .
a_M

Output

Print the number of ways to climb up the stairs under the condition, modulo 1\ 000\ 000\ 007.

Sample Input 1

6 1
3

Sample Output 1

4

There are four ways to climb up the stairs, as follows:

0 \to 1 \to 2 \to 4 \to 5 \to 6

0 \to 1 \to 2 \to 4 \to 6

0 \to 2 \to 4 \to 5 \to 6

0 \to 2 \to 4 \to 6

Sample Input 2

10 2
4
5

Sample Output 2

0

There may be no way to climb up the stairs without setting foot on the broken steps.

Sample Input 3

100 5
1
23
45
67
89

Sample Output 3

608200469

Be sure to print the count modulo 1\ 000\ 000\ 007.



Sample input:
6 1
3


Sample output:
4

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

    N, M = R()
    A = [r_int() for _ in range(M)]
    l = [0] * (N+1)
    pre_a = -1
    for a in A:
        l[a] = -1
        if pre_a + 1 == a:
            print(0)
            return
        pre_a = a
    
    for i in range(N+1):
        if i == 0:
            l[i] = 1
        elif i == 1 and l[i] != -1:
            l[i] = 1
        elif l[i] != -1:
            if l[i-2] == -1 or l[i-1] == -1:
                l[i] = l[i-1] + l[i-2] + 1
            else:
                l[i] = (l[i-2] + l[i-1]) % (10**9+7)
    print(l[N])
    
    # 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:
n,m=map(int,input().split())
#TLEの対策1. a in listと比べて a in setはめちゃんこ速い!!
a=set([int(input()) for _ in range(m)])

#TLEの対策2.配列ではなく変数を使う(対策1と比べると対して効果なし).
p,q=0,1

for i in range(1,n+1):
    #最新のp,q以前の値は捨てて良い.つまり配列を使用する必要なし.
    p,q=q,(p+q)%(10**9+7)*(not i in a) #n*Trueは1, n*Falseは0を表す.
print(q)

Submission status: Accepted

Solution code:
n, m = map(int, input().split())
A = [False for i in range(n+1)]
for i in range(m):
    a = int(input())
    A[a] = True

dp = [0 for i in range(n+1)]
dp[0] = 1

for i in range(1, n+1):
    if A[i]:
        dp[i] = 0
    else:
        dp[i] = (dp[i-1] + dp[i-2]) % 1000000007

print(dp[-1])

Submission status: Accepted

Solution code:
N, M = map(int, input().split())
A = [int(input()) for _ in range(M)]
dp = [-1] * (N+1)
dp[0] = 1
dp[1] = 1

for a in A:
    dp[a] = 0

for i in range(2,N+1):
    if dp[i] == 0:
        pass
    else:
        dp[i] = dp[i-1] + dp[i-2]

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

Submission status: Accepted

Solution code:
N, M = map(int, input().split())
aset = set([int(input()) for _ in range(M)])
MOD = 10**9 + 7
dp = [0] * (N + 1)
dp[0] = 1
dp[1] = 0 if 1 in aset else 1
for i in range(2, N + 1):
    if i not in aset:
        dp[i] = dp[i - 1] + dp[i - 2]
print(dp[-1] % MOD)

Submission status: Accepted

Solution code:
n, m = map(int, input().split())
a = {int(input()) for _ in range(m)}

mod = 10**9+7
dp = [0]*(n+1)
dp[0]=1

if not 1 in a:
  dp[1]=1

for i in range(2, n+1):
  if i in a:
    continue
  else:
    dp[i] = dp[i-1]+dp[i-2]

print(dp[n]%mod)

Submission status: Accepted

Solution code:
n, m = map(int, input().split())
a = [int(input()) for _ in range(m)]

dp = [-1]*(n+1)
dp[0] = 1
dp[1] = 1
for i in a:
    dp[i] = 0

for i in range(2, n+1):
    if dp[i] == 0:
        pass
    else:
        dp[i] = dp[i-1] + dp[i-2]
    
print(dp[n]%(10**9+7))

Submission status: Accepted

Solution code:
import math

def fib(n):
  if n==1:
    return 1
  elif n<=0:
    return 0
  tmp1,tmp2=1,2
  for _ in range(n-2):
    tmp1,tmp2=tmp2,tmp1+tmp2
  return tmp2

n,m=map(int,input().split())
if m==0:
  print(fib(n)%1000000007)
  exit()
a=[int(input()) for _ in range(m)]
ans=1

if n==2 and a[0]==1:
  print(1)
  exit()

for i in range(m):
  if i==0 and a[0]==1:
    pass
  if i==0 and a[0]!=1:
    ans*=fib(a[i]-1)
  elif i>0 and a[i]-a[i-1]==2:
    pass
  elif i>0 and a[i]-a[i-1]!=2:
  	ans*=fib(a[i]-a[i-1]-2)
  ans%=1000000007
  
if n-a[-1]>1: 
  ans*=fib(n-a[-1]-1)
ans%=1000000007
print(ans)

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a={int(input()) for _ in range(m)}
mod=10**9+7

dp=[0]*(n+1)
dp[0]=1
if 1 not in a:
   dp[1]=1

for i in range(2,n+1):
      if i in a:
            continue
      else:
            dp[i]=dp[i-2]+dp[i-1]
print(dp[-1]%mod)

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a=[]
for i in range(m):
    a.append(int(input()))
dp=[0]*(n+1)
dp[0]=1
dp[1]=1
if 1 in a:
    dp[1]=0
a=set(a)
for i in range(2,n+1):
    if i in a:
        continue
    dp[i]=dp[i-1]+dp[i-2]
print(dp[-1]%(10**9+7))

Submission status: Accepted

Solution code:
def main():
    INF = 10 ** 9 + 7
    N, M, *a = map(int, open(0).read().split())
    a = set(a)
    dp = [0] * (N + 1)
    dp[:2] = 1, 1 if 1 not in a else 0
    for i in range(2, N + 1):
        if i not in a:
            dp[i] = (dp[i - 1] + dp[i - 2]) % INF
    print(dp[-1])
    return


main()

Submission status: Accepted

Solution code:
def main():
    INF = int(1e9+7)
    N, M, *a = map(int, open(0).read().split())
    a = set(a)
    dp = [0] * (N + 1)
    dp[:2] = 1, 1 if 1 not in a else 0
    for i in range(2, N + 1):
        if i not in a:
            dp[i] = (dp[i - 1] + dp[i - 2]) % INF
    print(dp[-1])
    return


main()

Submission status: Accepted

Solution code:
INF = int(1e9+7)


def main():
    N, M, *a = map(int, open(0).read().split())
    a = set(a)
    dp = [0] * (N + 1)
    dp[:2] = 1, 1 if 1 not in a else 0
    for i in range(2, N + 1):
        if i not in a:
            dp[i] = (dp[i - 1] + dp[i - 2]) % INF
    print(dp[-1])
    return


main()

Submission status: Accepted

Solution code:
INF = int(1e9+7)


def modadd(a, b):
    # aとbを足した値をmodする(a + b mod p)
    return (a + b) % INF


def main():
    N, M, *a = map(int, open(0).read().split())
    a = set(a)
    dp = [0] * (N + 1)
    dp[:2] = 1, 1 if 1 not in a else 0
    for i in range(2, N + 1):
        if i not in a:
            dp[i] = modadd(dp[i - 1], dp[i - 2])
    print(dp[N])
    return


main()

Submission status: Accepted

Solution code:
from sys import stdin
INF = int(1e9+7)
readlines = stdin.readlines


def modadd(a, b):
    # aとbを足した値をmodする(a + b mod p)
    return (a + b) % INF


def main():
    lines = readlines()
    N = int(lines[0].split()[0])
    a = set(map(int, lines[1:]))
    dp = [0] * (N + 1)
    dp[:2] = 1, 1 if 1 not in a else 0
    for i in range(2, N + 1):
        if i not in a:
            dp[i] = modadd(dp[i - 1], dp[i - 2])
    print(dp[N])
    return


main()

Submission status: Accepted

Solution code:
import sys

n, m = map(int, sys.stdin.readline().split())
A = [int(sys.stdin.readline()) for _ in range(m)]
bloken = [0 for i in range(n+1)]
for a in A:
    bloken[a]=1
    

dp = [0 for i in range(n+1)]
dp[0] =1
#print(dp)

for i in range(1, n+1):
    if bloken[i]==1:
        continue
    if i-2>=0:
        dp[i] = dp[i-1] + dp[i-2]
    else:
        dp[i] = dp[i-1]


print(dp[-1]%1000000007)

Submission status: Accepted

Solution code:
n,m = map(int,input().split())
mat = [0 for i in range(n+1)]

for i in range(m):
    mat[int(input())] = -1

for i in range(n):
    if i == 0:
        mat[i] = 1
    if mat[i] == -1:
        continue
    if i + 1 < n+1:
        if mat[i+1] != -1:
            mat[i+1] += mat[i]
    if i + 2 < n+1:
        if mat[i+2] != -1:
            mat[i+2] += mat[i]
if mat[-1] >= 0:
    print(mat[-1]%1000000007)
else:
    print(0)

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a=[]
for i in range(m):
    a.append(int(input()))
ans=[10*9]*n
ans[0]=1
for i in range(m):
    ans[a[i]-1]=0
if len(ans)>1 and ans[1]!=0:
    ans[1]=ans[0]+1
for j in range(n-2):
    if ans[j+2]==0:
        continue
    else:
        ans[j+2]=ans[j+1]+ans[j]
        ans[j+2]=ans[j+2]%(1000000007)
    #print(ans)
print(ans[n-1])
#print(ans)

Submission status: Accepted

Solution code:
mod = 10**9+7
N, M = map(int, input().split())
a = set(int(input()) for _ in range(M))

dp = [0] * (N + 1)
dp[:2] = 1, 1 if 1 not in a else 0

for i in range(2, N+1):
    # in listでは間に合わない
    if not i in a:
        dp[i] = (dp[i-1] + dp[i-2]) % mod
print(dp[-1])

Submission status: Accepted

Solution code:
N,M =map(int,input().split())
a = [int(input()) for i in range(M)]
DP = [1]*N
mod = 10**9 + 7
for i in a:
    DP[i-1] = 0
if(N != 1):
    for i in range(N):
        if(DP[i] != 0):
            if(i<1):
                DP[i] = DP[i-1]%mod
            else:
                DP[i] = (DP[i-2] + DP[i-1])%mod
else:
    DP = [1]
print(DP[-1])

Submission status: Accepted

Solution code:
N, M = map(int,input().split())
dp = [0]*(N+1)
broke = [0]*(N+1)
dp[0] = 1
dp[1] = 1

for _ in range(M):
    a = int(input())
    broke[a] = -1

for i in range(N-1):
    if broke[i] != -1 and broke[i+1] != -1:
        dp[i+2] = dp[i+1] + dp[i]
    elif broke[i] == -1and broke[i+1] != -1:
        dp[i+2] = dp[i+1]
    elif broke[i+1] == -1and broke[i] != -1:
        dp[i+2] = dp[i]
    else:
        print(0)
        exit()
# print(broke)
# print(dp)
MOD = 10**9+7
print(dp[N]%MOD)

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a=[]
for i in range(m):
    a.append(int(input()))
dp=[None]*(n+1)
dp[0]=1
dp[1]=1
if 1 in a:
    dp[1]=0
for i in a:
    dp[i]=0
for i in range(2,n+1):
    if dp[i]!=0 :
        dp[i]=dp[i-1]+dp[i-2]
print(dp[-1]%(10**9+7))

Submission status: Accepted

Solution code:
import sys

n, m = map(int, input().split(' '))
a = [True] * (n+1)

for i in range(m):
  num = int(input())
  a[num] = False

dp = [0] * (n+1)
dp[0] = 1
for i in range(n+1):
  
  if (i+1) <= (n):
    if a[i+1]:
      dp[i+1] = dp[i] + dp[i+1]
      dp[i+1] = dp[i+1] % (10**9 + 7)
  if (i+2) <= (n):
    if a[i+2]:
      dp[i+2] = dp[i] + dp[i+2]
      dp[i+2] = dp[i+2] % (10**9 + 7)
  

# print(a)
print(dp[n])

Submission status: Accepted

Solution code:
N,M = map(int,input().split())
A = set([int(input()) for _ in range(M)])
dp = [0]*(N+1)
dp[0] = 1
for i in range(1,N+1):
    dp[i] = (dp[i-1] + dp[i-2])%(1000000007)
    if i in A:dp[i] = 0
    
print(dp[N])

Submission status: Accepted

Solution code:
n, m = (int(i) for i in input().split()) 
a = [int(input()) for i in range(m)] 
is_broken = [1] * n
dp = [0] * (n + 1)
dp[0] = 1
mod = 1000000007
for i in a:
  is_broken[i] = 0

for i in range(n):
  if i >= 1:
    dp[i+1] = dp[i] * is_broken[i] + dp[i-1] * is_broken[i-1]
  else:
    dp[i+1] = dp[i] * is_broken[i]
print(dp[n]%mod)

Submission status: Accepted

Solution code:
fib=[0,0,1,2]
for i in range(4,100005):
  fib.append(fib[i-1]+fib[i-2])

n,m=map(int,input().split())
a=[int(input()) for i in range(m)]

a=set(a)

p,q=0,1

for i in range(1,n+1):
  p,q=q,(p+q)%(10**9+7)*(not i in a)

print(q)

Submission status: Accepted

Solution code:
import sys
input = sys.stdin.readline
N, M = [int(x) for x in input().strip().split()]
A = set([int(input()) for _ in range(M)])
s = 1
s_ = 0
for n in range(1, N+1):
  if n in A:
    s, s_ = 0, s
    continue
  s, s_ = s + s_, s
print(s % (10 ** 9 + 7))

Submission status: Accepted

Solution code:
import sys
input = sys.stdin.readline
N, M = [int(x) for x in input().strip().split()]
A = set([int(input()) for _ in range(M)])
s = [0 for _ in range(N + 1)]
s[0] = 1
if 1 not in A:
  s[1] = 1

for n in range(2, N+1):
  if n in A:
    continue
  else:
    s[n] = s[n-1] + s[n-2]
print(s[-1] % (10 ** 9 + 7))

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a={int(input()) for i in range(m)}

dp=[0]*(n+1)
dp[0]=1
if 1 in a:
      dp[1]=0
else:
      dp[1]=1

for i in range(2,len(dp)):
      if i in a:
            continue
      dp[i]=(dp[i-2]+dp[i-1])
      
print(dp[-1]%(10**9+7))

Submission status: Accepted

Solution code:
import sys 
sys.setrecursionlimit(10**6)

n, m = map(int, input().split())
a = [int(input()) - 1 for _ in range(m)]
a.append(n)

dp = [-1] * max(3, n + 1)
dp[0] = 1
dp[1] = 1
dp[2] = 2
def stepsum(n):
    if dp[n] != -1:
        return dp[n]
    dp[n] = stepsum(n-1) + stepsum(n-2)
    return dp[n]
prev = 0
ans = 1
for ai in a:
    if prev != 0 and ai - prev < 0:
        ans = 0
        break
    ans *= stepsum(ai - prev)
    prev = ai + 2

print(ans % ( 10 ** 9 + 7 ))

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a={int(input()) for i in range(m)}
mod=10**9+7

x=1 if 1 not in a else 0
dp=[1,x]+[0]*(n-1)

for i in range(2,n+1):
    if i in a:
        continue
    dp[i]=(dp[i-1]+dp[i-2])
print(dp[-1]%mod)

Submission status: Accepted

Solution code:
n, m = map(int, input().split())
a = [int(input()) for i in range(m)]
ans = [1] * (n + 1)
for i in a:
    ans[i] = 0
for i in range(2, n + 1):
    if ans[i]:
        ans[i] = ans[i - 1] + ans[i - 2]
    if ans[i] >= 1000000007:
        ans[i] = ans[i] % 1000000007
print(ans[-1])

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a=set([int(input()) for i in range(m)])
dp=[0]*(n+1)
dp[0]=1
for i in range(1,n+1):
    dp[i]=(dp[i-1]+dp[i-2])%(10**9+7)
    if i in a:
      dp[i]=0
print(dp[n])

Submission status: Accepted

Solution code:
N,M = map(int, input().split())
a_list = [int(input()) for _ in range(M)]

tmp =  [1]*(N+1)
for a in a_list:
    tmp[a] = 0
for i in range(2,N+1):
    if tmp[i]:
        tmp[i] = tmp[i-1]+tmp[i-2]
    if tmp[i]> 1000000007:
        tmp[i] = tmp[i] % 1000000007
print(tmp[-1] % 1000000007)

Submission status: Accepted

Solution code:
import math
import fractions
mod=1000000007
(n,m)=map(int,input().split())
a=[0]*(n+2)
b=[0]*(n+2)
for i in range(m):
    t=int(input())
    a[t]=1
b[0]=1
for i in range(n+1):
    if(a[i]==1):
        b[i]=0
        continue
    if(i==0):
        continue
    if(i==1):
        b[i]=b[i-1]
        continue
    b[i]=(b[i-1]+b[i-2])%mod

print(b[n]%mod)

Submission status: Accepted

Solution code:
n,m=map(int,input().split())
a=0
cnt=1
p,q,r=1,0,0
#print(cnt,p)
for i in range(m):
  a=int(input())
  while cnt<n and cnt<a:
      s,r,q=r,q,p
      p=(q+r)%(10**9+7)
      cnt+=1
      #print(cnt,p)
  if a==cnt:
    s,r,q=r,q,p
    p=0
    cnt+=1
    #print(cnt,p)
    
while cnt<=n:
    s,r,q=r,q,p
    p=(q+r)%(10**9+7)
    cnt+=1
    #print(cnt,p)
print(p%(10**9+7))

Submission status: Accepted

Solution code:
N, M = map(int, input().split())
A = [int(input()) for _ in range(M)]
MOD = 10**9+7

is_safe = [True]*(N+1)
for a in A:
    is_safe[a] = False

dp = [0]*(N+1)
# 初期条件
dp[0] = 1
if is_safe[1]:
    dp[1] = 1

for i in range(2, N+1):
    if is_safe[i-1]:
        dp[i] += dp[i-1]
    if is_safe[i-2]:
        dp[i] += dp[i-2]
    dp[i] %= MOD

print(dp[N])

Submission status: Accepted

Solution code:
#c dp version
n,m = map(int,input().split())
a=[]
for i in range(m):
    a.append(int(input()) )
from collections import deque
a=deque(a)
mod=10**9 + 7

dp=[0]*(n+2)
dp[0]=0
dp[1]=1
aa=0
if len(a)>0:
    aa=a.popleft()
for i in range(2,n+2):
    if i-1 == aa:
        dp[i]=0
        if len(a)>0:
            aa=a.popleft()
    else:
        dp[i]=( dp[i-1]+dp[i-2] )%mod
print(dp[-1])

Submission status: Accepted

Solution code:
n, m = map(int, input().split())
count = [[0, False] for _ in range(n+2)]
for _ in range(m):
    a = int(input())
    count[a][1] = True
count[n][0] = 1

for i in range(n)[::-1]:
    if count[i][1] and count[i+1][1]:
        print(0)
        exit(0)
    if count[i][1]:
        continue
    count[i][0] = (count[i+1][0] + count[i+2][0])
print(count[0][0] % 1000000007)

Submission status: Accepted

Solution code:
# DP
N, M = map(int, input().split())
broken = set([int(input()) for _ in range(M)])

MOD = 10**9+7
dp = [0 for i in range(N+2)]
dp[N] = 1

for i in reversed(range(N)):
    if i in broken:
        continue
    dp[i] = dp[i+1] + dp[i+2]
    dp[i] %= MOD

print(dp[0])

Submission status: Accepted

Solution code:
n, m = map(int, (input().split()))
a = {int(input()) for i in range(m)}
mod = 10 ** 9 + 7
 
x = 1 if 1 not in a else 0
dp = [1, x] + [0] * (n - 1)
 
for i in range(2, n + 1):
    if i in a:
        continue
    dp[i] = (dp[i - 1] + dp[i - 2])
 
print(dp[-1] % mod)