Submission #2612732

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pp;
typedef pair<ll,ll> pll;
void read(int& x){ scanf("%d",&x); }
void read(ll& x){ scanf("%lld",&x); }
template<typename T,typename... Args>
void read(T& a,Args&... b){ read(a); read(b...); }
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define eb emplace_back
#define x first
#define y second

ll n,a,b,k;

ll fact[300010];
const ll mod = 998244353;

ll Pow(ll b, ll e){
	if(e<0) e=(-e)*(mod-2)%(mod-1);
	ll ret=1;
	while(e){
		if(e&1) (ret*=b)%=mod;
		(b*=b)%=mod; e>>=1;
	}
	return ret;
}

ll Comb(ll n, ll r){
	return fact[n]*Pow(fact[r], -1)%mod*Pow(fact[n-r], -1)%mod;
}

int main()
{
	read(n,a,b,k);
	fact[0]=1;
	for(int i=1; i<=n; ++i) fact[i]=fact[i-1]*i%mod;
	ll ans = 0;
	for(int p=0; p<=n; ++p){
		ll q = (k-p*a)/b;
		if(p*a + q*b == k && 0<=q && q<=n){
			(ans += Comb(n, p) * Comb(n, q) % mod) %= mod;
		}
	}
	printf("%lld\n", ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void read(int&)’:
./Main.cpp:6:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
 void read(int& x){ scanf("%d",&x); }
                                  ^
./Main.cpp: In function ‘void read(ll&)’:
./Main.cpp:7:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
 void read(ll& x){ scanf("%lld",&x); }
                                   ^

Judge Result