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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#791771#9553. The Hermithhu_yjhTL 924ms24612kbC++142.0kb2024-11-28 20:46:592024-11-28 20:47:04

Judging History

你现在查看的是最新测评结果

  • [2024-11-28 20:47:04]
  • 评测
  • 测评结果:TL
  • 用时:924ms
  • 内存:24612kb
  • [2024-11-28 20:46:59]
  • 提交

answer

#include <bits/stdc++.h>
#define dbg() cout<<"-------"
typedef  long long ll;
using namespace std;
typedef pair<int,int> PII;
typedef unsigned long long ull;
const int N=2e6+10;
const int mod=998244353;
ll n,m;
ll dp[N][20];
ll fact[N];
ll qmi(ll x,ll y,ll mod){
    ll res=1,t=x%mod;
    while(y){
        if(y&1) res=res*t%mod;
        t=t*t%mod;
        y>>=1;
    }
    return res;
}
ll c(int n,int m){
    if(m>n) return 0;
    return fact[n]*qmi(fact[m],mod-2,mod)%mod*qmi(fact[n-m],mod-2,mod)%mod;
    //return fact[n]*qmi(fact[m]*fact[n-m]%mod,mod-2,mod)%mod;
}
void solve(){
    cin>>m>>n;
    fact[0]=1;for(int i=1;i<=m;i++) fact[i]=fact[i-1]*i%mod;
    //cout<<c(3,0)<<'\n';
   //  cout<<"*****"<<'\n';
    for(int i=1;i<=m;i++) dp[i][1]=1;

    for(int len=1;len<=17;len++){
        for(int i=1;i<=m;i++){
            for(int j=2*i;j<=m;j+=i){
                dp[j][len+1]+=dp[i][len];
                dp[j][len+1]%=mod;
            }
        }
    }
   // cout<<dp[1][1]<<' '<<dp[1][2]<<'\n';
 //   cout<<"..."<<'\n';
    
    ll ans=0;
    for(int i=1;i<=m;i++){
        int cnt=m/i-1;
        ans+=(c(m-i,n-1)-c(cnt,n-1))*n%mod;
        //cout<<i<<"..."<<ans<<'\n';
        ans%=mod;
    }
    //cout<<ans<<'\n';
  //  exit(0);
  //ans=0;/////////////////
    for(int g=1;g<=m;g++){
        for(int len=1;len<=min(18ll,n-1);len++){
            for(int t=2*g;t<=m;t+=g){
                int cnt=m/g-t/g;
                int cnt2=m/t-1;
                ans+=(c(cnt,n-len-1)-c(cnt2,n-len-1))%mod*dp[g][len]%mod*(n-len)%mod;
                // if((c(cnt,n-len-1)-c(cnt2,n-len-1))*dp[g][len]%mod*(n-len)%mod){
                //     cout<<g<<' '<<len<<" "<<t<<'\n';
                // }
                ans%=mod;
            }
        }
      //  cout<<g<<"..."<<ans<<'\n';
    }
    cout<<((ans%mod)+mod)%mod<<'\n';



}
int main(){
    
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t;
    //cin>>t;
    t=1;
    while(t--){
        solve();
    }
} 

Details

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Test #1:

score: 100
Accepted
time: 1ms
memory: 5572kb

input:

4 3

output:

7

result:

ok 1 number(s): "7"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5688kb

input:

11 4

output:

1187

result:

ok 1 number(s): "1187"

Test #3:

score: 0
Accepted
time: 174ms
memory: 24612kb

input:

100000 99999

output:

17356471

result:

ok 1 number(s): "17356471"

Test #4:

score: 0
Accepted
time: 82ms
memory: 7840kb

input:

11451 1919

output:

845616153

result:

ok 1 number(s): "845616153"

Test #5:

score: 0
Accepted
time: 924ms
memory: 20808kb

input:

99998 12345

output:

936396560

result:

ok 1 number(s): "936396560"

Test #6:

score: 0
Accepted
time: 105ms
memory: 20820kb

input:

100000 1

output:

0

result:

ok 1 number(s): "0"

Test #7:

score: -100
Time Limit Exceeded

input:

100000 15

output:


result: