Submission #10273434

Source Code Expand

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import sys
stdin = sys.stdin
ns = lambda: stdin.readline().rstrip()
ni = lambda: int(stdin.readline().rstrip())
nm = lambda: map(int, stdin.readline().split())
nl = lambda: list(map(int, stdin.readline().split()))
n,a,b = nm()
mod = 10**9 + 7
s = pow(2,n,mod) - 1
def fur(n,r):
    p,q = 1,1
    for i in range(r):
        p = p*(n-i)%mod
        q = q*(i+1)%mod
    return p * pow(q,mod-2,mod) % mod
print((s - fur(n,a) - fur(n,b)) % mod)
 
 
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import sys

stdin = sys.stdin

ns = lambda: stdin.readline().rstrip()
ni = lambda: int(stdin.readline().rstrip())
nm = lambda: map(int, stdin.readline().split())
nl = lambda: list(map(int, stdin.readline().split()))

n,a,b = nm()
mod = 10**9 + 7
s = pow(2,n,mod) - 1

def fur(n,r):
    p,q = 1,1
    for i in range(r):
        p = p*(n-i)%mod
        q = q*(i+1)%mod
    return p * pow(q,mod-2,mod) % mod

print((s - fur(n,a) - fur(n,b)) % mod)

Submission Info

Judge Result