Submission #33272208

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Source Code Expand

#include <bits/stdc++.h>

#define eprintf(args...) fprintf(stderr, args)
#define rep(i, n) for (int i = 0; i < (int)(n); ++ i)

using i64 = long long;

const int mxn = 3e5 + 5;
const int mod = 998244353;

inline int qpow(int x, int n) {
	int ans = 1;
	for (; n; n >>= 1, x = 1LL * x * x % mod)
		if (n & 1) ans = 1LL * ans * x % mod;
	return ans;
}

int fac[mxn], ifac[mxn];
std::map <int, std::vector <int> > rem;

inline int comb(int x, int y) {
	if (y < 0 || y > x) return 0;
	if (x < mxn) return 1LL * fac[x] * ifac[y] % mod * ifac[x - y] % mod;
	if ((int) rem[x].size() <= y) {
		for (int i = (int) rem[x].size(); i <= y; ++ i) {
			rem[x].push_back(i ? 1LL * rem[x].back() * (x + mod - i + 1) % mod : 1);
		}
	}
	return 1LL * rem[x][y] * ifac[y] % mod;
}

int n;
i64 K;
int p2[mxn];

int main() {
	rep(i, mxn) fac[i] = i ? 1LL * i * fac[i - 1] % mod : 1;
	ifac[mxn - 1] = qpow(fac[mxn - 1], mod - 2);
	for (int i = mxn - 1; i; -- i) ifac[i - 1] = 1LL * i * ifac[i] % mod;
	rep(i, mxn) p2[i] = i ? 2LL * p2[i - 1] % mod : 1;
	scanf("%d %lld", &n, &K);
	K %= mod;
	int ans = 0;
	for (int i = 0; i <= n; ++ i) {
		int cur = 0;
		cur = (cur + 1LL * (K + 1) * comb(K, n - i)) % mod;
		cur = (cur + mod - 1LL * (n - i) * comb(K + 1, n - i + 1) % mod) % mod;
		ans = (ans + 1LL * comb(n, i) * p2[n - i] % mod * cur) % mod;
	}
	printf("%d\n", ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:41:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   41 |  scanf("%d %lld", &n, &K);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~

Judge Result