Submission #2656387

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Source Code Expand

/*
    
*/
#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn=1000000,ha=998244353;
inline int add(int x,int y){ x+=y; return x>=ha?x-ha:x;}
inline void ADD(int &x,int y){ x+=y; if(x>=ha) x-=ha;}

inline int ksm(int x,int y){
	int an=1;
	for(;y;y>>=1,x=x*(ll)x%ha) if(y&1) an=an*(ll)x%ha;
	return an;
}

int jc[maxn+5],ni[maxn+5],n,m,ans;

inline int C(int x,int y){ return x<y?0:jc[x]*(ll)ni[y]%ha*(ll)ni[x-y]%ha;}

inline void init(){
	jc[0]=1;
	for(int i=1;i<=maxn;i++) jc[i]=jc[i-1]*(ll)i%ha;
	ni[maxn]=ksm(jc[maxn],ha-2);
	for(int i=maxn;i;i--) ni[i-1]=ni[i]*(ll)i%ha;
}

inline void solve(){
	for(int i=1;i<=m;i++)
	    ADD(ans,C(i<<1,i)*(ll)C(n+m-i*2,n-i)%ha);
	
}

int main(){
	init();
	
	scanf("%d%d",&n,&m);
	if(n<m) swap(n,m);
	
	solve();
	
	ans=ans*(ll)ni[2]%ha*(ll)ksm(C(n+m,n),ha-2)%ha;

	ADD(ans,n);
	printf("%d\n",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:37:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^

Judge Result