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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#762740#9553. The Hermitwsxcb#WA 141ms24748kbC++171.4kb2024-11-19 16:27:442024-11-19 16:27:51

Judging History

你现在查看的是最新测评结果

  • [2024-11-19 16:27:51]
  • 评测
  • 测评结果:WA
  • 用时:141ms
  • 内存:24748kb
  • [2024-11-19 16:27:44]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define se second
#define fi first
const int N=1e5+5,mod=998244353;
//#define int long long
int ans=0;
ll fac[N],invfac[N];
ll ksm(ll a,ll b){
	ll ans=1;
	while(b){
		if(b&1)ans=ans*a%mod;
		a=a*a%mod;b/=2; 
	}
	return ans%mod;
}
ll C(int x,int y){
	if(x<y)return 0;
	return fac[x]*invfac[y]%mod*invfac[x-y]%mod;
}
int m,n;
ll dp[N][25];
void add(ll &x,ll y){
	x+=y;
	if(x>=mod)x-=mod;
}
ll get(ll x,ll y){
	ll ans=C(x,y);
	if(y>x)return 0;
	for(int i=2;i<=x+1;i++){
		int c=(x+1)/i-1;
		ans=(ans-C(c,y-1));
		if(ans<0)ans+=mod;
	}
	return ans%mod;
}
void solve(){
	
	cin>>m>>n;
	fac[0]=1;
	
	for(int i=1;i<=m;i++)fac[i]=fac[i-1]*i%mod;
	invfac[m]=ksm(fac[m],mod-2);
	for(int i=m-1;i>=0;i--)
	invfac[i]=invfac[i+1]*(i+1)%mod;
	ans=1ll*C(m,n)*n%mod;
	//cout<<ans<<'\n';
	ll res=0;
	for(int i=1;i<=m;i++){
		dp[i][1]++;
		for(int j=i+i;j<=m;j+=i){
			for(int k=1;k<20;k++){
				add(dp[j][k+1],dp[i][k]);
			}
		}
	}
	//cout<<get(2,2)<<'\n';
	for(int i=1;i<=20;i++){
		for(int j=1;j<=m;j++){
			int x=m/j-1;
			ll g=dp[j][i]*get(x,n-i)%mod*i%mod;		
			ans-=g;
			//cout<<ans<<'\n';
			if(ans<0)ans+=mod;
		}
	}
	cout<<ans<<'\n';
}
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	int t=1;
	//cin>>t;
	while(t--){
		solve();
	}
	return 0; 
} 

Details

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Test #1:

score: 100
Accepted
time: 0ms
memory: 5648kb

input:

4 3

output:

7

result:

ok 1 number(s): "7"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5768kb

input:

11 4

output:

1187

result:

ok 1 number(s): "1187"

Test #3:

score: 0
Accepted
time: 56ms
memory: 24748kb

input:

100000 99999

output:

17356471

result:

ok 1 number(s): "17356471"

Test #4:

score: 0
Accepted
time: 3ms
memory: 8032kb

input:

11451 1919

output:

845616153

result:

ok 1 number(s): "845616153"

Test #5:

score: 0
Accepted
time: 61ms
memory: 24728kb

input:

99998 12345

output:

936396560

result:

ok 1 number(s): "936396560"

Test #6:

score: -100
Wrong Answer
time: 141ms
memory: 24692kb

input:

100000 1

output:

776108950

result:

wrong answer 1st numbers differ - expected: '0', found: '776108950'