Submission #4467770

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Source Code Expand

#include<stdio.h>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn = 1e6+6;
const int mod = 998244353;
int add(int x,int y) { x+=y; return x>=mod?x-mod:x; }
int sub(int x,int y) { x-=y; return x<0?x+mod:x; }
int mul(int x,int y) { return 1ll*x*y%mod; }
int ksm(int a,int b) {
	int ans = 1;
	for(;b;b>>=1,a=mul(a,a))
		if(b&1) ans = mul(ans,a);
	return ans;
}
int fac[maxn],inv[maxn];
int GC(int x,int y) {
	if(x<y) return 0;
	return mul(fac[x],mul(inv[x-y],inv[y]));
}
int n,m;
int ans;
int main() {
	scanf("%d%d",&n,&m);
	if(n<m) swap(n,m);
	fac[0] = 1; for(int i=1;i<=2*n;i++) fac[i] = mul(fac[i-1],i);
	inv[2*n] = ksm(fac[n*2],mod-2);
	for(int i=2*n-1;i>=0;i--) inv[i] = mul(inv[i+1],i+1);
	for(int i=1;i<=m;i++) {
		ans = add(ans,mul(GC(i+i,i),GC(n+m-i-i,n-i)));
	}
	ans = mul(ans,ksm(2*GC(n+m,m)%mod,mod-2));
	ans = add(ans,n);
	printf("%d",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:26:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^

Judge Result