Submission #4567454

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=2000010,ha=998244353;
int n,m,inv[N],fac[N],invfac[N];
int qpow(int a,int b)
{
    int re=1;
    while(b)
    {
        if(b&1)re=re*a%ha;
        a=a*a%ha,b>>=1;
    }
    return re;
}

int C(int x,int y)
{
    return fac[x]*invfac[y]%ha*invfac[x-y]%ha;
}
signed main()
{
    invfac[0]=fac[0]=1;
    for(int i=1;i<=2000000;i++)inv[i]=qpow(i,ha-2),fac[i]=fac[i-1]*i%ha,invfac[i]=invfac[i-1]*inv[i]%ha;
    scanf("%lld%lld",&n,&m);
    if(n>m)swap(n,m);
    int ans=n*C(n+m,n)%ha;
    for(int i=1;i<=n;i++)
        ans=(ans-C(i+i-1,i)*C(m-i+n-i,m-i)%ha+ha)%ha;
    printf("%lld",(n+m-ans*qpow(C(m+n,m),ha-2)%ha+ha)%ha);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:25:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld%lld",&n,&m);
                            ^

Judge Result