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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#797356#9553. The HermitHalloWorldWA 2ms5232kbC++201.5kb2024-12-02 21:25:162024-12-02 21:25:17

Judging History

你现在查看的是最新测评结果

  • [2024-12-02 21:25:17]
  • 评测
  • 测评结果:WA
  • 用时:2ms
  • 内存:5232kb
  • [2024-12-02 21:25:16]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define SZ(x) ((int)(x).size())
#define debug(a) cout<<#a<<":"<<a<<endl
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define per(i,b,a) for(int i=b;i>=a;i--)
constexpr int N=100010;
constexpr int INF=2e9;
constexpr ll LLF=2e18;
constexpr ll mod=998244353;
constexpr int dir[4][2]={{-1,0},{1,0},{0,-1},{0,1}};
ll powmod(ll a,ll b,ll mod=mod) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
//ll inv(ll a){return powmod(a,mod-2);}
ll n,m,ans=0;
ll inv[N],inc[N];
void init(){
	inc[0]=1; for(int i=1;i<N;i++) inc[i]=inc[i-1]*i%mod;
	inv[N-1]=powmod(inc[N-1],mod-2);
	for(int i=N-2;i>=1;i--) inv[i]=inv[i+1]*(i+1)%mod;
}
ll C(int a,int b){	
	if(b==0) return 1;
	if (a<b) return 0; if (a==b) return 1;
	return inc[a]*inv[a-b]%mod*inv[b]%mod;
}
ll f[N][31];
void solve() {
	init();
	cin>>m>>n;
	ans=C(m,n)*n%mod;
	rep(i,1,m) f[i][1]=1;
	rep(i,2,30)rep(j,1,m){
		for(int k=2;k*j<=m;k++){
			f[k*j][i]=(f[k*j][i]+f[j][i-1])%mod;
		}
	}
	rep(i,1,30)rep(j,1,m){
//		cout<<j<<" "<<i<<" "<<f[j][i]<<"\n";
		if(n-i>=0){
			ll k=C((m/j)-1,n-i);
//			cout<<j<<" "<<f[j][i]<<" "<<k<<'\n';
			if((m/j)-1>=1) ans=(mod+ans-f[j][i]*C((m/j)-1,n-i)%mod)%mod;
			else ans=(mod+ans-f[j][i])%mod;
		}	
	}
	cout<<ans<<'\n';
}
int main() {
	ios::sync_with_stdio(false);cin.tie(nullptr);
	//cout<<fixed<<setprecision(10);
	//	int testcase;cin>>testcase;rep(_,1,testcase){
	solve();
	//	}
	return 0;	
}

Details

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Test #1:

score: 0
Wrong Answer
time: 2ms
memory: 5232kb

input:

4 3

output:

2

result:

wrong answer 1st numbers differ - expected: '7', found: '2'