Submission #1542625

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Source Code Expand

#include<cstdio>
#include<algorithm>
using namespace std;
long long Mod = 998244353, F[1001000], InvF[1001000], S, S2, S3;
long long Pow(long long a, long long b){
    long long r = 1;
    while(b){
        if(b&1)r=r*a%Mod;
        a=a*a%Mod;b>>=1;
    }
    return r;
}
long long Inv(long long a){return Pow(a,Mod-2);}
long long Get(int a, int b){
    return F[a+b] * InvF[a] % Mod * InvF[b] % Mod;
}
int n, m;
int main(){
    int i;
    F[0]=1;
    for(i=1;i<=1000000;i++)F[i]=F[i-1]*i%Mod;
    InvF[1000000] = Inv(F[1000000]);
    for(i=1000000;i>=1;i--)InvF[i-1] = InvF[i] * i % Mod;
    scanf("%d%d",&n,&m);
    if(n > m) swap(n,m);
    S = m * Get(n,m) % Mod;
    for(i=0;i<n;i++){
        S = (S + Mod - Get(i, m-n+i) * Get(n-i, n-i-1) % Mod * (n-i-1) % Mod) % Mod;
        S = (S + Get(i, m-n+i+1) * Get(n-i-1, n-i-1) % Mod * (n-i-1) % Mod) % Mod;
        
        S3 = (S3 + Get(i, m-n+i) * Get(n-i, n-i-1) % Mod * (n-i) % Mod) % Mod;
        S3 = (S3 + Mod - Get(i, m-n+i+1) * Get(n-i-1, n-i-1) % Mod * (n-i-1) % Mod) % Mod;
    }
    S=(S+S3)%Mod;
    printf("%lld\n",S * Inv(Get(n,m))%Mod);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:24:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
                        ^

Judge Result