Problem p02768 (python)

Fixed submission:
mod=10**9+7
n,a,b=map(int,input().split())
ans=pow(2,n,mod)-1 #n種類の花を使って花束を作る総数は2^n-1通り
comb1=1 #nCaの計算
for i in range(n-a+1,n+1): #n*(n-1)*…*(n-a+1)を計算
 comb1*=i
 comb1%=mod
for i in range(1,a+1): #1/a!=1/(1*2*…*a)=1^(p-2)*2^(p-2)*…*a^(p-2) (p=10**9+7)を計算
 comb1*=pow(i,mod-2,mod)
 comb1%=mod
comb2=1
for i in range(n-b+1,n+1): #n*(n-1)*…*(n-b+1)を計算
 comb2*=i
 comb2%=mod
for i in range(1,b+1): #1/b!=1/(1*2*…*b)=1^(p-2)*2^(p-2)*…*b^(p-2) (p=10**9+7)を計算
 comb2*=pow(i,mod-2,mod)
 comb2%=mod
ans-=(comb1+comb2) #nCa、nCbを総数から引く
ans%=mod
print(ans)

Buggy submission (verdict: Runtime Error):
def cmb(n, r, p):
	if (r < 0) or (n < r):
		return 0
	r = min(r, n - r)
	return fact[n] * factinv[r] * factinv[n - r] % p


def cmb(n, r, p):
	if (r < 0) or (n < r):
		return 0
	r = min(r, n - r)
	return fact[n] * factinv[r] * factinv[n - r] % p


p = 10 ** 9 + 7
N = 10 ** 6  # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p)
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用

for i in range(2, N + 1):
	fact.append((fact[-1] * i) % p)
	inv.append((-inv[p % i] * (p // i)) % p)
	factinv.append((factinv[-1] * inv[-1]) % p)


n,a,b=map(int,input().split())
ans=((pow(2,n)-1)%(10**9+7)-cmb(n,a,p)%p-cmb(n,b,p)%p)
print(int(ans))

Buggy submission (verdict: Runtime Error):
def cmb(n, r, p):
	if (r < 0) or (n < r):
		return 0
	r = min(r, n - r)
	return fact[n] * factinv[r] * factinv[n - r] % p


p = 10 ** 9 + 7
N = 10 ** 6  # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p)
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用

for i in range(2, N + 1):
	fact.append((fact[-1] * i) % p)
	inv.append((-inv[p % i] * (p // i)) % p)
	factinv.append((factinv[-1] * inv[-1]) % p)


n,a,b=map(int,input().split())
ans=((2**n-1)%(10**9+7)-cmb(n,a,p)%p-cmb(n,b,p)%p)
print(int(ans))

Buggy submission (verdict: Runtime Error):
def cmb(n, r, p):
	if (r < 0) or (n < r):
		return 0
	r = min(r, n - r)
	return fact[n] * factinv[r] * factinv[n - r] % p


p = 10 ** 9 + 7
N = 10 ** 6  # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p)
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用

for i in range(2, N + 1):
	fact.append((fact[-1] * i) % p)
	inv.append((-inv[p % i] * (p // i)) % p)
	factinv.append((factinv[-1] * inv[-1]) % p)


n,a,b=map(int,input().split())
ans=((2**n-1)%p-cmb(n,a,p)-cmb(n,b,p))
print(0 if ans<0 else ans)

Buggy submission (verdict: Runtime Error):
def cmb(n, r, p):
	if (r < 0) or (n < r):
		return 0
	r = min(r, n - r)
	return fact[n] * factinv[r] * factinv[n - r] % p


p = 10 ** 9 + 7
N = 10 ** 6  # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p)
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用

for i in range(2, N + 1):
	fact.append((fact[-1] * i) % p)
	inv.append((-inv[p % i] * (p // i)) % p)
	factinv.append((factinv[-1] * inv[-1]) % p)


n,a,b=map(int,input().split())
ans=((2**n-1)%(10**9+7)-cmb(n,a,p)-cmb(n,b,p))
print(int(ans))

Buggy submission (verdict: Runtime Error):
def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod

mod = 10**9+7 #出力の制限
N = 10**4
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )

n,a,b=map(int,input().split())
ans=((2**n-1)%(10**9+7)-cmb(n,a,mod)-cmb(n,b,mod))
print(ans)

Buggy submission (verdict: Runtime Error):
def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod

mod = 10**9+7 #出力の制限
N = 10**4
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )

n,a,b=map(int,input().split())
ans=((2**n-1)%(10**9+7)-cmb(n,a,mod)-cmb(n,b,mod))
print(ans)