Buggy python submission (verdict: Time Limit Exceeded):
from math import factorial

n, m = map(int, input().split())
A = [0] * m
for i in range(m):
    A[i] = int(input())
B = []
if m > 1:
    for i in range(m - 1):
        if A[i + 1] - A[i] == 1:
            print(0)
            exit()
if m:
    B.append(A[0])
    A.append(n + 1)
    for i in range(len(A) - 2, -1, -1):
        B.append(A[i + 1] - A[i] - 1)
else:
    B.append(n + 1)
div = 1000000007
ans = 1
for b in B:
    if b < 3:
        continue
    c = b - 1
    two_max = c // 2
    a = 0
    for two in range(two_max + 1):
        one = c - (2 * two)
        a += factorial(one + two) // (factorial(one) * factorial(two))
    ans *= a
    ans %= div
print(ans)


Fixed submission:
def generate_range_combinations(n):
    C = [1] * n
    for i in range(2, n):
        C[i] = (C[i - 1] + C[i - 2]) % DIV
    return C


def solve(n, m, A):
    from collections import defaultdict

    if m == 0:
        C = generate_range_combinations(n + 1)
        return C[-1]

    D = defaultdict(lambda: 0)
    for i in range(m - 1):
        d = A[i + 1] - A[i] - 1
        if d == 0:
            return 0
        D[d] += 1
    D[A[0]] += 1
    D[n - A[-1]] += 1

    ans = 1
    C = generate_range_combinations(max(D.keys()))
    for k, v in D.items():
        ans *= C[k - 1] ** v
        ans %= DIV
    return ans


DIV = 1000000007
n, m = map(int, input().split())
A = [int(input()) for _ in range(m)]
print(solve(n, m, A))

Buggy python submission (verdict: Time Limit Exceeded):
from math import factorial

n, m = map(int, input().split())
A = [0] * m
for i in range(m):
    A[i] = int(input())
B = []
if m > 1:
    for i in range(m - 1):
        if A[i + 1] - A[i] == 1:
            print(0)
            exit()
if m:
    B.append(A[0])
    A.append(n + 1)
    for i in range(len(A) - 2, -1, -1):
        B.append(A[i + 1] - A[i] - 1)
else:
    B.append(n + 1)
div = 1000000007
ans = 1
for b in B:
    if b < 3:
        continue
    c = b - 1
    two_max = c // 2
    a = 0
    for two in range(two_max + 1):
        one = c - (2 * two)
        a += factorial(one + two) // (factorial(one) * factorial(two))
    ans *= a
    ans %= div
print(ans)


Fixed submission:
def generate_range_combinations(n):
    C = [1] * n
    for i in range(2, n):
        C[i] = (C[i - 1] + C[i - 2]) % DIV
    return C


def solve(n, m, A):
    from collections import defaultdict

    if m == 0:
        C = generate_range_combinations(n + 1)
        return C[-1]

    D = defaultdict(lambda: 0)
    for i in range(m - 1):
        d = A[i + 1] - A[i] - 1
        if d == 0:
            return 0
        D[d] += 1
    D[A[0]] += 1
    D[n - A[-1]] += 1

    ans = 1
    C = generate_range_combinations(max(D.keys()))
    for k, v in D.items():
        ans *= C[k - 1] ** v
        ans %= DIV
    return ans


DIV = 1000000007
n, m = map(int, input().split())
A = [int(input()) for _ in range(m)]
print(solve(n, m, A))

Buggy python submission (verdict: Runtime Error):
from math import factorial

n, m = map(int, input().split())
A = [0] * m
for i in range(m):
    A[i] = int(input())
B = []
if m > 1:
    for i in range(m - 1):
        if A[i + 1] - A[i] == 1:
            print(0)
            exit()
if m:
    B.append(A[0])
    A.append(n + 1)
    for i in range(len(A) - 2, -1, -1):
        B.append(A[i + 1] - A[i] - 1)
else:
    B.append(n + 1)
div = 1_000_000_007
ans = 1
for b in B:
    if b < 3:
        continue
    c = b - 1
    two_max = c // 2
    a = 0
    for two in range(two_max + 1):
        one = c - (2 * two)
        a += factorial(one + two) // (factorial(one) * factorial(two))
    ans *= a
    ans %= div
print(ans)


Fixed submission:
def generate_range_combinations(n):
    C = [1] * n
    for i in range(2, n):
        C[i] = (C[i - 1] + C[i - 2]) % DIV
    return C


def solve(n, m, A):
    from collections import defaultdict

    if m == 0:
        C = generate_range_combinations(n + 1)
        return C[-1]

    D = defaultdict(lambda: 0)
    for i in range(m - 1):
        d = A[i + 1] - A[i] - 1
        if d == 0:
            return 0
        D[d] += 1
    D[A[0]] += 1
    D[n - A[-1]] += 1

    ans = 1
    C = generate_range_combinations(max(D.keys()))
    for k, v in D.items():
        ans *= C[k - 1] ** v
        ans %= DIV
    return ans


DIV = 1000000007
n, m = map(int, input().split())
A = [int(input()) for _ in range(m)]
print(solve(n, m, A))