Submission #2359343

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Source Code Expand

#include<cstdio>
typedef long long ll;
const int mod=998244353;
int N,M;
ll fac[1<<20],ifac[1<<20];
ll inv(int a,int p=mod){return a==1?1:(1+p*(a-inv(p%a,a)))/a%p;}
ll C(int n,int m){return fac[n]*ifac[m]%mod*ifac[n-m]%mod;}
int main(){
	scanf("%d%d",&N,&M);
	for(int i=*fac=1;i<=N+M;i++)fac[i]=fac[i-1]*i%mod;
	ifac[N+M]=inv(fac[N+M]);
	for(int i=N+M;i;i--)ifac[i-1]=ifac[i]*i%mod;
	int ans=C(N+M,N)*(N>M?N:M)%mod;
	for(int x=1;x<=N&&x<=M;x++)ans=(ans+C(x*2-1,x)*C(N+M-x*2,N-x))%mod;
	ans=ans*inv(C(N+M,N))%mod;
	printf("%d\n",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:9:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&M);
                     ^

Judge Result