提出 #32446296

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ソースコード 拡げる

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 5000005, mod = 998244353;
int n, a, b, c;
int fac[N], inv[N];
int ans;

int qpow(int x, int y) {
	int res = 1;
	while (y) {
		if (y & 1) res = 1ll * res * x % mod;
		x = 1ll * x * x % mod;
		y >>= 1;
	}
	return res;
}

void init(int maxn) {
	fac[0] = 1;
	for (int i = 1; i <= maxn; ++i) fac[i] = 1ll * fac[i - 1] * i % mod;
	inv[maxn] = qpow(fac[maxn], mod - 2);
	for (int i = maxn - 1; ~i; --i) inv[i] = 1ll * inv[i + 1] * (i + 1) % mod;
}

int C(int n, int m) {
	if (n < 0 || m < 0 || n < m) return 0;
	return 1ll * fac[n] * inv[m] % mod * inv[n - m] % mod;
}

void add(int &a, int b) {
	a += b;
	if (a >= mod) a -= mod;
	if (a < 0) a += mod;
}

void mul(int &a, int b) {
	a = 1ll * a * b % mod;
}

int main() {
	scanf("%d%d%d%d", &n, &a, &b, &c);
	init(5000000);
	for (int i = 0; i <= n; ++i) {
		//枚举有i行空着，然后容斥：g(0)=(-1)^i*f(i),i=0~n
		int x = C(n, i);
		int tmp1 = 0, tmp2 = 0, tmp3 = 0;
		for (int j = 0; j <= a; ++j) add(tmp1, C(n - i, j));
		for (int j = 0; j <= b; ++j) add(tmp2, C(n - i, j));
		for (int j = 0; j <= c; ++j) add(tmp3, C(n - i, j));
		mul(x, tmp1), mul(x, tmp2), mul(x, tmp3);
		if (i & 1) add(ans, -x);
		else add(ans, x);
	}
	printf("%d", ans);
	return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:42:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   42 |  scanf("%d%d%d%d", &n, &a, &b, &c);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

ジャッジ結果