Submission #2607571

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Source Code Expand

#include <bits/stdc++.h>

#define itn int
#define all(x) (x).begin(), (x).end()
#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())

using namespace std;

inline int nxt() {
	int x;
	scanf("%d", &x);
	return x;
}

const int mod = 998244353;
const int N = 333333;
long long fact[N];
long long inv[N];
long long invfact[N];

long long C(int n, int k) {
	return fact[n] * invfact[k] % mod * invfact[n - k] % mod;
}

int main() {
	fact[0] = invfact[0] = 1;
	for (int i = 1; i < N; ++i) {
		inv[i] = (i == 1) ? 1 : mod - mod / i * inv[mod % i] % mod;
		fact[i] = fact[i - 1] * i % mod;
		invfact[i] = invfact[i - 1] * inv[i] % mod;
		assert(inv[i] * i % mod == 1);
	}

	int n = nxt(), a = nxt(), b = nxt();
	long long k;
	cin >> k;

	long long ans = 0;
	for (int i = 0; i <= n; ++i) {
		long long l = 1ll * i * a;
		if (k < l) {
			break;
		}
		long long kk = k - l;
		if (kk % b) {
			continue;
		}
		long long lb = kk / b;
		if (lb > n) {
			continue;
		}
		ans += 1ll * C(n, i) * C(n, lb) % mod;
	}
	cout << ans % mod << "\n";

	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int nxt()’:
./Main.cpp:11:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &x);
                 ^

Judge Result