Submission #70656894

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Source Code Expand

mod = 998244353

n, m, s = map(lambda s_: int(s_), input().split())
nn = 10**6
fact = [1] * nn
for i in range(nn - 1):
    fact[i + 1] = fact[i] * (i + 1) % mod
invfact = [1] * nn
invfact[nn - 1] = pow(fact[nn - 1], mod - 2, mod)
for i in range(nn - 1)[::-1]:
    invfact[i] = invfact[i + 1] * (i + 1) % mod

def binom(x, y):
    if x < 0 or y < 0 or x - y < 0:
        return 0
    return fact[x] * invfact[y] % mod * invfact[x - y] % mod


ans = 0
for i in range(n + 1):
    d = s - i * (m + 1)
    if d < 0:
        break
    b = binom(d + n - 1, n - 1)
    ans += binom(n, i) * (-1)**i * b % mod
ans %= mod
print(ans)

Submission Info

Judge Result